TRACK worker protection during construction works has always been a safety priority for KiwiRail, New Zealand's state-owned railway. With an annual asset renewal budget of $NZ 300m ($US 246.6m) and $NZ 1.5bn investment in upgrading the urban rail networks in Auckland and Wellington during the last five years, there is a growing potential conflict between an increase in workload and worker safety.
Typically, workers are protected by the application of different types of worksite safety rules and procedures which offer differing levels of protection. The lowest level for workers on live track is working under the supervision of safety observers to warn of approaching trains. More extreme forms allow for the complete closure of lines to enable work to take place unhindered.
For a number of years KiwiRail has investigated improvements to one of its intermediate levels of protection. This form allows staff to work on live track through the use of so-called compulsory stop protection (CSP).
Current CSP procedure requires that a series of caution, whistle, and stop boards are erected starting at a point 2km from the worksite. The driver of an approaching train must bring it to a halt at the compulsory stop board and radio ahead to the worksite to get authority to pass beyond the stop board and into the worksite.
Previous investigations into safety improvements for CSP have focused on off-the-shelf products which operate as an electronic overlay to improve worksite awareness of approaching trains. This is typically achieved through the use of a locomotive detection unit with a communications link to the worksite that activates audible and visual alerts.
We realised quickly that these existing products do not meet our needs so we developed our own electronic worksite protection system creating a concept called the simplified Electronic Worksite Protection System (Eprotect).
Eprotect detects whether a locomotive has failed to stop before reaching the stop board. If this occurs, it will automatically activate the emergency brakes on the locomotive, bringing the train to a forced stop, thereby providing an independent backup to the driver.
The current manual CSP system has a significant element of human involvement which encompasses voice communications, and relies on the driver paying attention and worksite protection staff setting up the boards. All of these create opportunities for error and resultant safety issues.
Consequently, KiwiRail management and staff are working with the Rail and Maritime Transport Union (RMTU) to substantially remove the hazard of unauthorised trains overrunning into CSP worksites.
There is an unacceptable number of incidents a year that arise from the current protection system. These occur either through trains proceeding beyond stop boards when unauthorised, or when trains are authorised to enter worksites that are not clear of personnel or equipment. This initiative is the first step in removing these safety issues.
The new system's technology centres around the Kupe Mobile Controller (KMC) and the Tranzlog equipment currently installed on locomotives. This has been designed and manufactured to our specifications by two local companies, Xworks and Otari Electronics.
GPS monitoring, facilitated by the KMC, which has previously been uploaded with active worksite locations, tracks a locomotive's approach to a worksite. The KMC identifies the location where the locomotive should stop to conform to correct CSP procedure. Should the locomotive fail to stop as required, Tranzlog, via instruction from the KMC, activates the locomotive's emergency brakes thereby automatically bringing it to a stop.
Off-the-shelf GPS technologies like this are not readily available for use in the KiwiRail environment. Similar European locomotive stopping functionality could be adapted for use by KiwiRail but at a significant cost per locomotive and it would not take advantage of the existing KMC and Tranzlog functionality we have readily available.
System malfunctioning is allayed by internal fault checking undertaken by the system during normal operation. Eprotect continually self-monitors and provides alerts to a fault escalation process should system problems occur.
Eprotect is the first milestone in the development of an electronic worksite protection system envisaged to provide all rail safety and productivity improvement benefits. We regard track worker protection as a priority when undertaking any construction projects, something that is fully supported by KiwiRail CEO Jim Quinn. "Safety in the workplace is crucial for KiwiRail. Not only do we want to maintain our existing safety standards but we are also looking to continually improve our approach. This is something that is shown by the Eprotect initiative" Through the smart use of appropriate technologies KiwiRail is certain that it is possible to develop a safety-critical protection system which allows a step-change in worksite safety and productivity benefits through maximising track worker time on track, and moving away from having to stop trains prior to entering worksites by guaranteeing they are safe and clear of track workers.
The Eprotect intermediate step is focused on getting the first stage of safety improvements into the field quickly. It achieves this by efficiently using existing KiwiRail equipment within locomotives. This positive step will improve worksite safety and will be used as a secondary protection overlay to the current CSP procedure.
System rollout will begin before the end of the year on part of the East Coast Main Trunk lines. The next challenge will be to continue the technical development of the complete worksite protection system.
We have identified and tested the radio technologies we believe will provide the best integration of safety functionality and track worker ease-of-use in the field. To make this system concept a deployable product we now need to engage a development partner to turn our testing into reality.