The paper discusses one of the most important stages in the developed methodology for building a strategy of maintenance of railway vehicles, which is the RAMS analysis (Reliability, Availability, Maintainability, Safety) in the area of safety. The paper presents the application of RAMS analysis in the construction process (development or change) of the maintenance strategy on the example of a 6Dg diesel locomotive. Based on the conducted research, it was found that this analysis enables proper classification of hazards, quantification of the frequency of occurrence of hazards and the adoption of the appropriate criteria for risk assessment of the created strategy.

The article presents the issues of ensuring the quality and safety of food products in road transport. The article discusses selected legal acts related to road transport of food, including the Agreement on the International Carriage of Perishable Foodstuffs and on the Special Equipment to be Used for such Carriage (ATP) and the Hazard Analysis and Critical Control Points System (HACCP). The general characteristics of the entire process of transporting food products were presented and vehicles adapted to carry it out were discussed. Next, refrigerated semitrailers were described, as well as requirements for temperatures and vehicles in which the entire food supply process takes place. An analysis of statistical data on the transport of food products in Poland in the years 2008-2016 was also carried out.

Ensuring a high level of reliability of the transport system is one of the most important issues related to the proper functioning of this system. It is concerned with the delivery of the transported goods on time and in accordance with recipient’s order specification. The means of transport used in the delivery process are exposed to many external factors that may affect the reliability and safety of supply. Therefore, modelling and assessing the reliability of these systems requires the use of appropriate calculation methods that take into account complex scenarios reflecting the conditions of actual operation and maintenance. The presented paper concerns the application of Dynamic Fault Tree (DFT) together with Monte Carlo simulation to assess the selected reliability and availability indicators for the given transport system. The assessment of reliability was done based on the typical probabilistic models for analysis of the time to failure and the time to repair assigned to the selected components. The proposed approach allows detecting the weakest components of the transport system and is the basis for the development of preventive maintenance tasks. The presented model of the transport system can be further developed and adapted to needs of the specific system.

The paper presents a description of methods of changing the maintenance strategy concerning measures of intervals between maintenance levels based on the example of a selected railway vehicle type. The process starts with monitoring the vehicle after it is put into operation and the operational database is built, through the statistical and RAMS analyses, to the approval of changes in the maintenance system documentation by qualified railway safety bodies. Following the applicable formal and legal requirements, one of the key problems involved in the introduction of changes in the railway vehicle maintenance system is an assessment of the proposed changes for safety.

Based on the example of 6Dg type diesel locomotives, the paper presents a new maintenance strategy concerning periodical checks at the P1 maintenance level. Currently, such locomotives are sent off to service points every 102 hours of operation or every 14 days for a P1 level check. Studies demonstrate that the average distance to be covered by a locomotive to arrive at a service point is in excess of 60.0 km, and the quantity of fuel consumed is more than 88 litres. It is costly and time consuming to have locomotives out of service and considerable resources of the railway carrier are engaged which could be made use of in the transport process. The aim of the newly developed strategy of P1 checks is to eliminate the need for locomotives to exit their routes to reach rolling stock maintenance points. The control/diagnostic and maintenance activities specified in the Maintenance System Documentation will be performed by so-called mobile maintenance points. The development of the new strategy required: identification of the current condition of the maintenance system, development of the concept of a new strategy of P1 maintenance checks, conduct of studies and operational analyses for SM42 series locomotives, performance of a durability, reliability analysis, assessment of safety together with an analysis of the risks involved in the proposed changes. In order to review and assess the efficiency of the new strategy, an observed operation of selected locomotives was conducted together with a railway carrier. During the study, the maintenance activities and processes were monitored and the costs of P1 checks were recorded. The analysis of efficiency of the new strategy of performing P1 checks without the need for a locomotive to exit its route to reach a rolling stock maintenance point demonstrated that depending on the distance covered by the locomotive to reach a maintenance point, the unit costs of a P1 level check are lower by up to 67.1% compared with the currently applied method.