Railways are expected to operate with ever increasing availability. The availability of railway systems and subsystems influences the overall operational availability. As the track circuit is a key component of railway signalling and control, it can contribute significantly to the loss of availability of the railway system. One way to increase the availability of the track circuit is by implementing a proper maintenance policy.

In this article, Petri-nets have been used to develop models for availability analysis of the track circuit for both time-based and condition-based maintenance. A sensitivity analysis has been performed to estimate the effect of maintenance parameters on availability performance using cost-benefit analysis.

The railway has been accepted as one of the most environmentally friendly modes of transport for goods and passengers. However, the railway sector is striving to increase its capacity to meet the growing demand for the transport of goods and passengers with a high level of punctuality in its services. Higher availability requires the effective operation and maintenance of infrastructure, often necessitating the implementation of cost-effective preventive maintenance strategies. Therefore, a higher availability target means higher maintenance investment. However, the question of setting the availability target for the infrastructure is not easy, as it involves many influencing decision parameters, apart from a good understanding of the network configuration and traffic density.

Railway networks that have a smaller number of trains and a low punctuality requirement do not require higher availability targets. The aim of this paper is to estimate the availability target for railway infrastructure based on the capacity and punctuality requirements of infrastructure managers and train operating companies.

The objectives of the paper are to develop an approach to i) estimating the capacity of the infrastructure based on the design and operational characteristics and evaluating the influence of infrastructure availability on the required capacity and ii) estimating the volume of primary and secondary delay due to failures and maintenance of the infrastructure and establishing the relationship between availability and punctuality requirements.

To achieve these objectives, an example is presented with parameters drawn from failure, maintenance and traffic data. Finally, a model has been developed in Petri-Nets to establish a relationship between availability, capacity and punctuality. Monte Carlo simulation is used to establish the relationship. The simulation results illustrate the effect of infrastructure availability on train delays and capacity.

The European Rail Traffic Management System (ERTMS) is a major venture initiated by the European Union in order to create an interoperable railway network within Europe. The manufacturers of the ERTMS strive to attain a competitive edge by demonstrating the efficiency of their systems. Achieving the optimal cost effectiveness is one of the significant ways to address the efficiency of the system and involves maximising the availability and minimising the life cycle cost of the system over the system life cycle. One of the important ways of maximising the cost effectiveness of the system is to optimise the maintenance policy. This paper demonstrates the estimation of the cost effectiveness of an ERTMS system. The degradation and repair process of the system is modelled by Petri-Nets. Failure, maintenance and cost data are used as parameters for the model. The model will be useful for systems that experience degradations and are subjected to imperfect maintenance.