Railway Track Maintenance Research Articles

Mechanism of resonance and cancellation for train-induced vibrations on bridges with elastic bearings

In this paper, the mechanism involved in the phenomena of resonance and cancellation in the train-induced vibrations of railway bridges with elastic bearings is explained using an analytical approach. The train is modelled as a sequence of moving loads of constant intervals. The vibration shape of the elastically supported beam is approximated by the combination of a flexural sine mode and a rigid body mode. The present results indicate that under certain conditions, resonances of much higher peaks can be excited on elastically supported beams by moving trains at much lower speeds than those on simply supported beams. The cancellation is a phenomenon more decisive than that of resonance, in that it can suppress the latter even when the condition of resonance is met. Moreover, the speed for cancellation to occur is generally independent of the support stiffness. To verify the analytical results presented herein, a field test was conducted on two adjacent elastically supported bridges in existing railway lines. In the design of railway bridges, it is important that the phenomenon of resonance not be overlooked, as it is harmful not only to the riding comfort of passengers, but to the maintenance of railway tracks.

A computer system for surveying railway alignments in Hong Kong

This paper describes various engineering surveying operations in the construction and maintenance of railway tracks through the functional modules of a specifically designed computer software. This software designs for the main functions of alignment. setting-out. as-built and right-of-way surveys. The software introduced is the RTS (Rail Transit Survey) ®. which has been used in railway projects by many international civil engineering contractors and railway corporations around the world.

A Computer System for Surveying Railway Alignments in Hong Kong

This paper describes various engineering surveying operations in the construction and maintenance of railway tracks through the functional modules of a specifically designed computer software. This software designs for the main functions of alignment. setting-out. as-built and right-of-way surveys. The software introduced is the RTS (Rail Transit Survey) ®. which has been used in railway projects by many international civil engineering contractors and railway corporations around the world.

Rail Track Maintenance Planning: An Assessment Model

In Australian rail freight operations, railway track maintenance makes up between 25 and 35 percent of total train operating costs. Models have shown that track maintenance costs can be reduced by 5 to 10 percent through improved planning. The Track Maintenance Planning Model (TMPM) has been developed to deal with the track maintenance planning function in the medium to long term. In contrast to traditional models, which mainly use expert systems, TMPM simulates the impacts of railway track conditions and related maintenance work by using an existing track degradation model. Track condition data from that model are used to determine whether safety-related speed restrictions are needed and what immediate maintenance work may be required for safe train operation. TMPM outputs the net present value of the financial benefits of undertaking a given maintenance strategy compared with a base-case maintenance scenario. This approach has an advantage over current models in investigating what-if scenarios. The track engineer can assess the possible benefits of reduced operating costs from upgrading track infrastructure or from improving maintenance equipment. Track maintenance and train operating costs also can be simulated over time. The results of applying the model to a test track section using several different maintenance strategies are presented.

Scheduling of railway track maintenance activities and crews

Before railway track maintenance crews can undertake any work, the allocation of activities to available time intervals in the train schedule as well as to crews must be undertaken. This paper puts forward a model aimed at determining the best allocation of maintenance activities and crews so as to mininise the disruption to and from scheduled trains and to reduce completion time. The model is subject to constraints such as available budget; maintenance activity precedence; track availability; and minimum travel time between track links. Solution to the model is found using the tabu search heuristic for which the neighbourhood is defined by swapping the order of jobs, maintenance crews, or both. Application to a 300 km track corridor with a four day planning horizon is discussed along with the impacts of modifying the number of maintenance crews. The optimal schedule achieved an 8% reduction in expected interference delay with the train schedule and a 7% reduction in average completion times, relative to the solution which was constructed manually.

Scheduling of Railway Track Maintenance Activities and Crews

Scheduling of Railway Track Maintenance Activities and Crews

Scheduling of railway track maintenance activities and crews

Scheduling of railway track maintenance activities and crews

IMPROVING THE PERFORMANCE OF TRACK LINING AND LEVELLING MACHINES.

An assessment of the effectiveness of a number of strategies for the control of lining and levelling on railway track maintenance machines, based on experience gained in the development of alternative control systems for use on British Rail. The genral requirements for and limitations of traditional smoothing techniques are compared and subjected to analysis. Alternative control methods are described and assessed for their suitability in replacing traditional systems. In particular, the control systems employed in the British Rail Automatic Track Alignment system are discussed.

The Turnover Process in Organizations: An Exploration of the Role of Met-Unmet Expectations

An assessment of the turnover process was undertaken with subjects of railway track maintenance crews. The differences between the responses of workers who left the crews and others who retained membership for the study were partially explained by the met-unmet expectations framework, and there was some evidence to suggest a variety of work related factors are a source of employee perceptions. However, to obtain a fuller understanding of the processes of employee reactions further theoretical articulation is required.

Health risk assessment of noise, hand-arm vibration and cold in railway track maintenance

Health risk assessment of noise, vibration and cold was carried out in track maintenance workers in Finland. A health survey among 252 workers and noise and vibration measurements of tools used in track maintenance work was performed, and audiograms were examined from 117 workers. Hand-held tamping machines had caused most of the exposure to noise and vibration in the track maintenance work. The present results showed how important it is also to take into account preventive and contributory factors when health risks are assessed. The predicted risk of hearing damage was 24%, but the observed value in a clinical study was only 15%, obviously due to the effect of hearing protectors. The prevalence of vibration-induced white finger (14%) was predicted quite well with the ISO 5349 standard, but no method was available to assess the risk of nerve disorders. The results showed that there are many limitations in health risk assessment used, e.g. behaviour and protection facilities had a great influence on the risk of frostbite.

Participative Goal Setting as a Strategy for Improving Performance and Job Satisfaction: A Longitudinal Evaluation with Railway Track Maintenance Gangs

A longitudinal field experiment of job change was conducted over a 1-year period with 42 geographically dispersed railway track maintenance gangs. Experimental groups that employed participative goal setting were compared with a control unit that continued to employ the traditional work procedures. When perceptual, behavioral and affective responses were evaluated, over eight trials, it was determined that there were significantly different responses between the experimental and control groups. Those incumbents who were engaged in participative goal setting reported higher perceived states of involvement in decision making and greater job satisfaction. It was also observed that goal setting and performance were positively related. The implications for these findings are discussed.

Veilig Werken Volgens Geschreven Procedures

Research in the field of written procedures (in an industrial context) has moved along two lines: regulating the performance of operators, especially in nuclear power plants, and creating effective technical manuals. The quality of such texts has remained a problem, perhaps because research has generally concentrated on superficial text features and task analysis, thereby neglecting the actual use (or non-use) of documents in working situations and the wider interests the organisation has in writing down procedures. A more promising strategy, along the lines of a distinction made by Rasmussen, is to concentrate on the relation between written procedures and the appropriate levels of human performance: skill based, rule based or knowledge based. In a case study (procedures for railway-track maintenance with uninterrupted train service), users described their problems with the written procedures as "lack of clarity", alluding to deficiencies in content and presentation. Further analysis revealed the following more specific problems: - unclear presentation: not designed as a job performance aid, awkward phraseology, unfit for easy reference; - too many detailed procedures; - unclear working situation: users often felt compelled to choose between following the procedures to the letter and accomplishing the jobs on schedule; - resistance to the predominating "control directing" function of the procedures, to the detriment of their "action directing" function; - lack of motivation, as a result of not having been involved in the drawing up of the procedures. The procedures had been conceived by the organisation on a rule based level. Due to the modus operandi of the human cognitive system, however, actual application of the procedures often takes place on a skill based level. Accordingly, it was decided to rewrite the procedures to a skill based level, i.e. to write very explicit instructions, specifying the actions to be taken by workers at every level in the organisation. From the present study it can be concluded that the usability of safety-related written instructions is not determined predominantly by their contents and their presentation, but also by at least the following factors: organisational context (working conditions, administrative control, safety policies); task involved; risk perception; feasible level of human functioning; frequency of error types; ergonomic possibilities; motivation of the users; knowledge and experience of the users.

A MODEL OF TIME HISTORY OF RAILWAY TRACK IRREGULARITIES AND ITS APPLICATIONS

The informations for time history of track conditions are the bases of decision making for railway track maintenance, which are selection of track structure, planning of works, giving of rectification criteria of track irregularity and etc.. In this paper a model of time history of track irregularities and its applications have been presented. By analyzing the railway track system and applying recent results of investigation and method of system dynamics, system equations are set up and the processes of the states are studied under conditions of transportation, track structure and rectification criteria. It is concluded that applicability of the model will hold widely, although some system equations must be comlemented by adding a few practical data.

Minimum Cost Maintenance in Heavy Haul Rail Track

This paper describes two complementary studies concerning the maintenance and replacement of heavy haul railway track. Minimum cost policies are derived using decision networks in one case and a group replacement model in the other. The results indicate relatively large cost savings on current practice.

On the Rational Evaluation of Railway-Track Irregularity and the Determination of its Allowable Limit

Since some years the irregularity index of railway-track has been adopted as a measure by which the track conditions are discriminated and the maintenance of railway-track is put in rational practice by Japanese National Railways authorities. In this paper we shall discuss some properties of this index and present a new measure named relative entropy which has an intimate relationship with the vibration of running car, and explain on the determination of the allowable limit of our irregularity measure related to the velocity of car.

On the Theory by Linear Programming for the Planning of Railway-Track Maintenance and its Applications

In recent years the operations research has been rapidly developed as a management science. One of the most typical processes in the operations research is linear programming used for the production planning. In this paper we shall present a new analytical method based on linear programming by which we can evaluate the optimal activity levels of railway track, and discuss the applications of our method to the management of railway track.