1. Introduction
The transport policy of the European Union (EU) aims to achieve a reduction of 60% in GHG emission by 2050; the transport system should become more competitive and efficient in its use of resources. To achieve this, more than 30% of road freight over 300 kilometres should be shifted to other modes such as rail or waterborne transport by 2030, and more than 50% should be shifted by 2050, facilitated by efficient and green freight corridors [
1].
The EU supports the development of rail freight corridors (RFCs). There are nine established RFCs focused on offering quality customer-oriented rail freight services with improved capacity and harmonised technical standards [
2,
3]. The RFCs reinforce the cooperation among infrastructure managers to increase the efficiency of cross-border traffic. Passenger and freight transport must use the same railway infrastructure, often interfering and putting pressure on the different schedules. Currently, passenger trains, even when delayed, still receive priority over freight trains, which negatively impacts the necessary flexibility and efficiency. Optimising the use of railway infrastructure is a complex and difficult task of railway infrastructure management [
4]. Therefore, numerous capacity studies are being performed to investigate what part of extra traffic can be absorbed by the existing infrastructure and how much investment will be required for new infrastructure [
5]. The results of these studies must be rapid and precise to know how many train paths can be offered to railway operators and how much railway traffic can be supported by the current network [
6]. These studies must also provide regional and national authorities as well as owners of the infrastructure with information that proves the investment in the development of the rail network to be necessary and financially worthwhile. Based on the analysis of the operational and technical parameters of the infrastructure, it is possible to determine the factors that influence the use of the railway line by planned traffic flow [
7]. The running time, planned and unplanned waiting time, and buffer time are decisive. Knowing these factors will enable infrastructure managers to take measures and, ultimately, will create a long-term strategy that will achieve the desired use of infrastructure capacity [
8,
9]. The main purpose of optimising the scope of railway infrastructure capacity is to adapt the technical parameters of railway infrastructure to the expected traffic flow and to clearly define and establish its capacity [
10,
11].
The aim of this research is to propose procedures that will simply and accurately determine the quantification of benefits for increasing the throughput performance of the line. For initial estimates and assessments of investment measures, it is advantageous to use analytical methods to determine the throughput performance. There is a need to research the qualitative factors of capacity indicators.
The subject of the case study is the RFC marked “Amber”, which connects the Mediterranean region with central Poland. This corridor has lines with longer single-track sections, meaning a lack of capacity. The methodological approach for determining the throughput performance in the anticipated timetable and the case study are approximated on a restrictive section of this north-south RFC corridor. The focus is a single-track section Kysak–Prešov, which is extremely busy with passenger and freight traffic.
Figure 1 shows the network of corridors in the “Amber” RFC, which is related to the assessed track. Several variants of infrastructural measures were explored in this study to increase the capacity.
2. Literature Overview
In railway transport, in the case of some railway infrastructure managers, it is customary to refer to the capacity as the line throughput performance; sometimes, the abbreviated term line throughput is also used [
12]. The throughput performance of rail freight corridors is described and analysed in the study by Kontaxi and Ricci [
13]. The different techniques for capacity calculation are divided into three main categories: synthetic, analytical, and analogical. The methodology of Railways of the Slovak Republic (introduced in Internal Regulation D24 [
14]) develops three approaches to determine the throughput performance—graphical, analytical, and a combination of both. Comparisons, analyses, and research with proposals for innovations of this methodology have been presented in both teaching books [
12,
15,
16] as well in several scientific studies [
17,
18,
19,
20,
21]. In order to determine the meaning limit of the relationship between the definition of capacity and throughput, the study by Gašparík and Šulko [
12] proposed a modified definition of capacity in the following wording: “The capacity of the railway infrastructure is determined by the number of train paths that can be planned in a certain time window on a certain part of the railway infrastructure, given the heterogeneity of the train types and the required quality of train traffic”.
The capacity of the main railway lines as well as the analysis of methodologies for its calculation are solved in research [
18] that focuses on the analytical determination of the practical capacity of main tracks and the issue of the required capacity. The studies describe and compare the methodology for calculating the throughput capacity under national and international conditions. The consequences of crisis situations on railway infrastructure were often observed to lead to a significant reduction in its throughput or a disruption of its traffic flows.
The capacity of the railway infrastructure is expressed by the number of train paths in a specific sequence of individual train types on a defined line section of the infrastructure for a certain time window; furthermore, it reflects the requirements for achieving the required quality of the transport process [
19,
20]. Capacity is therefore the usable throughput performance within the sequence of train routes. The term “timetable robustness” is also used, which refers to the ability to not increase, or reduce, the initial delay.
When examining and determining the capacity options in general and with respect to the railway infrastructure, it is necessary to consider the operating conditions. Even if the operation will mostly take place under stochastic conditions, it cannot be ruled out that the operating conditions will be deterministic on a certain track section [
22,
23]. The calculated throughput performance of individual technical devices is the basis for the assessment of a series of connected devices (cascade of service systems). The resulting throughput performance of a continuous sequence of several technical devices, e.g., entrance tracks as service lines in the establishment station, several stations and their connecting interstation or track sections, we may refer to it as the operational performance [
24,
25].
To assess investment measures in the railway infrastructure, the capacity of the railway infrastructure is evaluated using different methodologies, but most often using simulation procedures. The outcome of the simulation provides recommendations for future modifications of the infrastructure layout. For example, the International Union of Railways (abbreviated UIC) published its recommended methodology [
26], which is based on the graphic principle and prefers simulation procedures for the determination the degree of capacity utilisation.
The technical and mathematical bases for the calculation of the permeable performance of railway transport are proposed in [
27], which were used in the creation of a simulation program for the optimal organisation of railway operational work after the disruption of their operation. The relation between basic operational indicators has been researched by using the developed stochastic mesoscopic simulation model [
28]. A railway infrastructure capacity assessment via computer simulation method was performed in paper [
29] where the paper discussed the tools and possibilities for line segments selection to obtain proper spatial segments for improving the capacity using more advanced systems.
Railway control systems in operation were addressed in [
30,
31]. The dependencies of railway infrastructure capacity were described in [
17], with testing being conducted via a computer-based simulation model, which provided results for further research on the issue. Two hypotheses oriented towards researching the linear dependence of capacity on the number of train paths as well as the need for the capacity estimation of a whole track or for only one block section were tested. An efficiency of increasing the track speed using the OpenTrack simulation tool was presented in [
32,
33]; there was an emphasis on the operation capacity of rail freight corridors because of the mixed traffic, i.e., passengers and freight. The authors described the configuration of railway infrastructure elements that may have a potential impact on the capacity. Subsequently, indicators were proposed that could be used to detect possible changes in capacity due to train operation. In the last phase, the authors implemented several simulation scenarios in the OpenTrack software. Another set of OpenTrack simulations was also described in [
34,
35] as well as in similar research studies on railway simulations and modelling transport routes in rail transport [
36,
37]. Industry 4.0 has an impact on the modernisation of railway infrastructure. Industry 4.0 technologies have been widely used in the railway industry, which have been mainly focused on the maintenance and control tasks that are necessary in railway infrastructure [
38]. The compilation of the periodic train timetable in rail passenger transport is a new evolving trend that increases the efficiency of rail transport. For focused research on the operational reliability of a railway line operated by a periodic timetable, refer to [
39]. The authors of [
40] offered one way to contribute to this area, and thus raised and improved this method of organising rail transport. The authors proposed a methodology that evaluates the level of stability of periodic train traffic diagrams based on operational and infrastructural factors. The methodology identifies operational–infrastructural factors that affect the stability and reliability of periodic train traffic diagrams.
The aim of [
41] was the optimisation of distance between stops. The authors of [
42,
43] aimed to discover what track speed is effective in terms of shortening the travel time, traction energy consumption, and other operational indicators.
Assessing the impact of railway modernisation on the socio-economic regional development is described in [
44].
3. Materials and Methods
The main purpose of optimising the scope of the railway infrastructure capacity is to adapt the technical parameters of the railway infrastructure to the expected traffic flow and to clearly define and establish its capacity [
45]. The goal of capacity analysis is to determine the maximum number of trains that would be able to operate on a given railway infrastructure, during a specific time interval and given the operational conditions. Numerous approaches and tools have been developed to address this problem, and they have been based on traffic patterns [
46], single-track analytical models [
47], or algebraic approaches [
48].
The different techniques and methodologies for calculating the capacity can be divided into three main categories according to the used methodology, compiled data, and level of detail. They are, according to [
49]:
Synthetic: these methods use deterministic expressions, i.e., the variables contained in these cannot change their state and assume fixed values during the reference time. From the mathematical point of view, they are equations where the unknown quantities are mutually independent, and they are also called static;
Analytical: these methods use probabilistic expressions; from the mathematical point of view, they are equations where the unknown quantities are mutually dependent, and they are also called dynamic;
Analogical: these methods can be further divided into asynchronous methods (which covers methods that provide the optimisation of one or more variables) and synchronous methods (traffic simulation); for example, the optimisation methods are based on procedures that look for the minimisation of delays in mixed-speed traffic as well as on simulation methods that represent the evolution of advanced research and are often used to validate the results of other methods.
The use of the analytical method appears in-line for the scope of high-level analyses that identify the most appropriate infrastructure layouts and signalling systems to adopt in a long-term perspective, independently upon a specific timetable structure.
The capacity of a line is defined as the number of scheduled trains that can run on the line in the reference time. Key elements that have a direct influence on the value of the capacity are [
50]:
Geometrical configuration of the track;
Line and station layout;
Features of signalling systems;
Movement rules and corresponding minimum distance between trains;
Operation and maintenance planning.
In this research, we adapted the solution according to the Slovak infrastructure management rules and the regulations to determine the permeability of railway lines (Regulation “D24”: designation of the infrastructure manager), which use an analytical method [
14]. We present the basic principles of this methodology of determining the practical throughput performance here; subsequently, we propose an improved view of evaluating the results of the quality of duty operation performance.
To determine the throughput performance in the perspective timetable, it is necessary to apply the following methodological procedure, which uses the principles of mathematical statistics and probability [
15]. All of the calculations are performed for the boundary interstationary section that shows the lowest theoretical throughput. Trains are divided by category, where
N is the total number of trains,
i is a designation for a train type (Ex: express train; Reg: regional; Fr: freight running; Fc: freight commuter; Fex: freight express; Loc: locomotive) and
Ni is the number of trains in individual categories (types); for example,
NEx is the number of trains of type
Ex. The probability of a train of a given type is then determined from the relationship [
14]:
where:
- p(i)
is the probability of the ith category train running [-];
- Ni
is the number of trains in the ith category [trains];
- N
is the number of all trains on the track section [trains].
To determine the characteristics of the perspective train traffic diagram, it is necessary to know not only the probability of the train running, but also the probability of running a given sequence of trains. The probability for running a specified train sequence is calculated according to this equation [
12]:
where:
- p(i,j)
is the probability of running a sequence of trains of the ith and jth types [-];
- Nj
is the number of trains of the jth category [trains].
Probability is a relative quantity; therefore, instead of the probability of a sequence of trains, it is more appropriate to work with the frequency of their occurrence, which is determined according to the relationship [
12]:
where:
- h(i,j)
is the frequency of occurrences of trains of the i-th and j-th types [number of occurrences].
The basic approach is to determine the occupancy time for individual train sequences. They are calculated based on knowledge of running times, operating intervals, or subsequent intermediate times (see
Figure 2).
The train sequences themselves need to be analysed for four options of train sequences (see
Figure 2), while the occupancy time is usually related to one of the stations in the boundary section (usually the “lower” station) [
15]:
The sequence of the first train is even, and the second train is also even (occupancy time is the headway time, i.e., the time period between the departure of the first train from station B and the departure of the second, subsequent train from station B; in variant (a), the first train must pass until station B, while in case (b), only until the first train passes the passing point);
The sequence of the first train is odd, and the second train is even (occupancy time is the sum of the running time of the odd and even trains and the station interval in the “upper” station, i.e., the time period between the departure of the first train from station B and the arrival of the second train in the opposite direction to station B; in variant (b), the second train crosses at the passing point, and therefore we calculate the travel times of the trains only after the switch and vice versa);
The sequence of the first train is even, and the second train is odd (the occupancy time is the station interval in the “lower” station, to which we refer the calculation of the occupancy time);
The sequence of the first even-numbered train, the second even-numbered train (occupancy time is the headway time at the “lower” station, i.e., the time period between the arrival of the first train to station B and the arrival of the second, subsequent train to station B; in variant (a), the second train must pass from station A, while in case (b), the second train must only pass from the passing point).
It is necessary to conduct an analysis of the occupancy times for all possible train sequences according to the types of trains, considering whether a train is passing through a given station. If the interstation section is divided into more block sections, in the cases of one-by-one train sequences, the headways must be calculated and must emphasise whether the first train is slower or faster. The beneficial effect of increasing the practical throughput of the interstation section by building a crossing point is shown in
Figure 2b, which shows the analysis of the occupancy times of the interstation section after the construction of a new crossing point. The figure illustrates the shortening of the occupation times.
The total occupation time of the interstationary section of all trains Σ to (or To) is determined as the scalar product of the frequency table and table of the shortest occupation times, respectively, by compiling a table of total occupancy times of individual train sequences and the sum of their elements. The calculation table can be simplified by rounding the table of the number of sequences to whole numbers (according to common mathematical principles), but in such a way that the sum of the trains in the table remains the same.
In addition, null values can be omitted. In the case of a procedure based on the use of probability theory and mathematical statistics, the buffer time plays an important role.
Buffer time
Tbr is calculated as a difference between the time window
T and the total occupancy time
To and time of permanent operations
Ts, according to the formula [
15]:
The determination of the practical throughput performance considers the need for the maintenance of the infrastructure, and the device is also used to carry out other operations than its primary use. The calculation includes necessary buffer time (to remove eventual disorders or irregularities in the transport operation). The practical throughput performance is determined according to the formula [
14]:
where:
- n
is the practical throughput performance (capacity) [trains];
- T
is the time window [minutes];
- Tv
is the total time in which the operating device within the computing time is barred from operation due to prescribed inspections, repairs, and maintenance [minutes];
- Ts
is the total time of permanent manipulations, i.e., the time in which the operating device is occupied by other actions than those mentioned above [minutes];
- to
is the technological time of occupation for one train (calculated as an average train) [minutes];
- tbr
is the real average buffer time per train [minutes];
- tbt
is the needed buffer time per one train according to ŽSR methodology [minutes].
This applies for the evaluation of the throughput performance of the constructed train traffic diagram. For the assessment of the perspective train traffic diagram, the value of needed buffer time
tbt is used instead of real average buffer time
tbr in Equation (5). The condition for the feasibility of the train traffic diagram is:
tbr > tbt. The qualitative factor is the infrastructure occupation rate
So and the throughput utilisation coefficient
Kp [
15].
The determination of all required qualitative and quantitative indicators of practical throughput performance is shown in
Table 1.
For the evaluation of the quality of traffic operation, the most important indicator is the infrastructure occupation rate in addition to the practical throughput, throughput performance utilisation, and waiting time. According to the ŽSR methodology, the critical value of occupation rate
So = 0.67 was set [
14,
51]. If the critical value is exceeded, an insufficient capacity must be assumed, and the infrastructure is considered overloaded. However, this indicator does not account for the risk for the organisation of the traffic flow in terms of quality. Based on our own research [
15,
17,
19,
20,
21,
51], comparative studies, and the approach based on the knowledge of methodologies, we proposed to expand this indicator by the value of the optimal level of quality of throughput performance. This was determined with
So = 0.40 based on the research and knowing the realisation of the planned timetable. We determined the degree of occupancy according to the previous methodology as a critical (limit) value. From the point of view of the quality of operation, it is necessary that the value of the relevant capacity indicator does not, in principle, exceed the set optimal value. If the value of this indicator is higher than the optimal value, there is a risk of insufficient quality. The graph in
Figure 3 expresses the principal dependence of the range of traffic (number of train routes) and the level of quality.
As a rule, the capacity consumption is assessed in simulation procedures. When there is a lower occupancy, it can be assumed that the track line is not being sufficiently used.
Table 2 explains the connections between the track occupancy rate, the relationship to the optimal and critical value of capacity indicators, and the expected quality level.
4. Capacity Results
The case study focused on the Slovak part of the “Amber” freight corridor, specifically on the busiest single-track line section Kysak–Prešov. The motivation for this study was to investigate the impact of infrastructure measures on the throughput performance of an important international freight corridor. There are bottlenecks on the line, and both passenger and freight traffic are operated in this section. The interstationary section Prešov–Drienovská Nová Ves is marked as A in this research. The Drienovská Nová Ves–Ličartovce track section is marked as B. This is a flat section between the Prešov railway station and the Drienovská Nová Ves railway station, which spans 8.395 kilometres between the stations (traffic offices) and 6.590 m between the entrance signals [
52,
53]. The current profile of the track has relatively large radios of arcs; originally during construction, it was designed for a line speed of 100 km/h [
54].
Table 3 shows the quantitative and qualitative indicators of the practical throughput performance of the assessed track section after an analysis of the constructed timetable.
The determination of the current throughput performance was analysed in two interstationary sections:
The automatic signal block Torysa divides this interstationary section into two block sections. This enables the bundling of trains. This traffic organisation is shown in
Figure 4 where we define a traffic period for a train sequence. This is key for the occupancy time calculation. The results are shown in
Table 5. For each sequence (combination) of train type (in this case, freight running trains), the table shows the unrounded frequency of the train sequence occurrence according to Equation (3); the rounded occurrence is given as the number of sequences, the unit occupancy time according to the analysis for each train sequence (see
Figure 3 and
Figure 4), and the total occupancy time for the given train sequence are rounded values. The result of the calculation is the total occupancy time of all trains.
The result from
Table 5 is the total occupancy time; subsequently, we determined all required qualitative and quantitative indicators of the practical throughput performance (see
Table 6). Because
tbt <
tbr, the train traffic diagram is feasible. The practical throughput performance is 118 trains per day.
The determination of the throughput performance of the current state of the Drienovská Nová Ves–Ličartovce track section:
We proceeded in the same way as in the previous determination for the Prešov–Drienovská Nová Ves track section. The sum of the lower right corners for the individual quadrants provides the total occupancy times of the quadrants, which are listed in
Table 7.
Subsequently from
Table 7, we determined all required qualitative and quantitative indicators of the practical throughput performance, which are shown in
Table 8.
6. Discussion
In the research, we analysed the capacity of the narrow gate of the freight corridor track. The chosen analytical method is suitable for determining the prospective throughput performance. The case study focused on the Slovak part of the “Amber” freight corridor, specifically on the single-track section Kysak–Prešov. We obtained eight variants.
The main benefit of proposal A1 and B1 is the shortening of train running times. The running time between Prešov railway station and Ličartovce railway station will be reduced from the current 16 min to 13 min in both directions in the express train type (Ex). For passenger regional trains (Re), the reduction is from 22 min to 17 min. For freight running trains (Fr) in the direction from Prešov to Ličartovce, the reduction is from 20 min to 17 min, and it is from 20.5 to 19 min in the opposite direction. This difference is due to the height track slope of 15‰. Shortening the travel times will significantly increase the current throughput performance. In the Prešov–Drienovská Nová Ves track section, the current 118 trains per day would increase to 146 trains per day. In the Drienovská Nová Ves–Ličartovce track section, the current 144 trains per day would increase to 156 trains per day.
The construction of a new passing point instead of the automatic signal block Torysa at Haniska pri Prešove would have a positive impact on the capacity of the track. The significant disadvantage is the level crossing with the first and second class roads. For the construction of the passing point to be possible at all, a minimum level crossing with a first-class road must be built. From the point of view of transport organisation, it is necessary to modify the station safety device in the Prešov railway station, from which this passing point would be controlled. In addition, it would be necessary to have the exchanges heated on all switches in the passing point because of the weather in the winter. The advantage of building the passing point is the increase in the practical throughput from 134 trains per day to 165 trains per day. In addition, it would be much easier to transport freight trains during the day in the peak hours. Furthermore, if built, the noise would significantly increase due to the crossing of trains, especially freight transport.
The advantages of a partial double-track section at the Prešov railway station–automatic signal block Torysa section is the increase in the practical capacity of up to 198 trains per day and a significant reduction in the transmission of delays on passenger trains. Compared with the passing point, the impact of noise at the crossing would be significantly lower, as in most cases there would be a crossing on the track and not in the village. Another advantage is that there is a railway stop on the double-track section, which reduces operating intervals for passenger trains. Compared with proposal A4, the investment costs associated with the development of switches adjustment would be lower, as the track would be connected to the original loading track 1a. The disadvantage is the need to build an extra-level crossing with a first-class road at 13.223 km to remove the original platform of the Haniska pri Prešove railway stop and to build new platforms for both tracks. Another disadvantage is that the Kendice railway stop is located on a single-track section.
A partial double-tracking of the automatic signal block Torysa–Drienovská Nová Ves railway station section is similar to proposal A3. The practical throughput performance would increase to 201 trains per day. Compared with proposal A3, there would be less noise in the village during a possible crossing at the end of the double-track section. The advantage is the reduction of the transmission of delays between passenger trains, but this is smaller than in the case of proposal A3. The disadvantage is that Haniska pri Prešove railway stop is on a single-track section and the level crossing must be removed and replaced by the under-passing road. From the point of view of the capacity of the track section, the complete double-tracking of the Prešov–Drienovská Nová Ves track section is the best option. This proposal would increase the capacity of the line to up to 183 trains per day for the even direction and up to 178 trains per day for the odd direction. Compared with the crossing point and partial doubling of the track sections, there would be no increase in travel times nor an increase in the occupancy of approach sections due to train crossings. The disadvantage is the higher area of land required, the need to rebuild the railway stations, and the reconstruction of the head and modification of the station safety system in the nearby stations. From the point of view of investment costs, this is the most expensive solution.
It would also help to trace freight trains that have a crossing problem at the remote-controlled Ličartovce crossing point, which is located on a large slope of 12–13‰; this together with the arc reducing the effect of traction makes it significantly difficult for heavy and long freight trains to start. As in proposal A5, the double-track section allows for the maintaining of single-track operation in the case of closure. This is a significant benefit compared with the current situation, as alternative bus transport must be introduced in the Ličartovce–Drienovská Nová Ves track section due to space conditions. Buses will not enter the remote pass Ličartovce. To further increase the track speed in the Drienovská Nová Ves-Prešov track section, it would be possible to adjust the crossing of passenger trains in the Prešov–Lipany track section and to extend short turnovers in Lipany. In terms of the practical throughput, despite the doubling of the Drienovská Nová–Ličartovce track section, the throughput in the Ličartovce–Drienovská Nová Ves track section would not increase. It would also be necessary to build a level crossing instead of a crossing at 6.773 km, which is crossed by a first-class road.
We used analytical procedures to determine the practical throughput performance in the anticipated timetable. We received results for the specified range of traffic, to which we applied the new proposed classification from the point of view of the quality of operation. The correctness of setting the occupation rate limit So = 0.40 for the optimal throughput level was confirmed. The issue for discussion is the setting of the critical value. According to the Railways of the Slovak Republic, whose methodology used So = 0.67, this level can be evaluated as appropriately set. It is possible to discuss the harmonisation of this level with the UIC methodology which is mainly intended for simulation procedures, where the limit level of capacity utilisation is set at 60%. If we set So = 0.60, then we would evaluate variant A1 as unfeasible. Considering the several research scenarios carried out including the one presented, and the knowledge of the authors, we recommend keeping the critical value of the degree of occupancy So = 0.67 for analytical procedures.
We have confirmed that:
The use of the analytical approach is very useful for the identification of the most appropriate infrastructure layouts and signalling systems to adopt in a long-term perspective, independently upon a specific timetable structure;
The implementation of a simulation model is necessary for in-depth analyses aiming at the optimisation of the use of the capacity and timetable structure itself.
7. Conclusions
Rail transport must be coordinated at all management levels and is determined by technological processes. The main process is the planning of the transport volume and infrastructure configuration. When examining and determining the capacity of the railway line, it is necessary to consider the operating dimensions.
This paper introduces a method for determining the practical throughput performance in the anticipated train traffic diagram using probability calculus and mathematical statistics. The part of the “Amber” EU freight corridor which makes a bottleneck at the Prešov–Ličartovce track section on the Slovak part of the corridor on the Plaveč–Kysak–Košice line was divided into two parts for the purpose of determining the practical throughput performance. The paper contains the determination of the capacity of the line section regarding the current state and provides an overview of several proposals for increasing the capacity of the Prešov–Ličartovce track section. Each proposal contains a description of the determination of the throughput performance of this line, and tables with individual determinations and figures illustrate how the individual proposals would be implemented.
The travel time would be reduced to 33 min from Prešov to Košice. After the planned modernisation of the Kysak–Košice line section, the travel time would be reduced to less than half an hour. The advantage is that the delays are simultaneously transmitted at peak times at the intersection of express trains, and the presence of regional trains would be reduced at peak hours between Prešov railway station and Ličartovce railway station. Due to the increase in the track speed, it is necessary to modify several parts of the railway infrastructure, namely:
Platforms at the Haniska pri Prešove, Kendice, and Drienovská Nová Ves stops and stations;
Relocate the block signals in the Prešov–Drienovská Nová Ves track section to optimise the length of the block sections;
Modify the approach sections of level crossings signalling between Prešov and the Obišovce railway stop;
By changing the cant in the arc, it would be necessary to adjust the level crossing at 6.773 km through the first-class road.
The modernisation of this track section with the application of individual proposals is of international importance and has an impact on the capacity of the railway corridor.
Nevertheless, further developments of the research should include a larger testing phase to systematically check the sensibility of the results to various timetable structures and to different signalling systems, e.g., according to the various European Rail Traffic Management System (ERTMS) levels. The optimisation and simulation methods must be adapted to each application environment [
49]. The three levels represent a general methodology for capacity management, where the first level represents a preliminary solution and the second level obtains a desired train schedule, which is validated by simulation software (as the third level). Therefore, the current trend is to develop tools with an integrated methodology that embed analytical, optimisation, and simulation approaches [
58].