West Coast Rail Modernization Train Protection And Warning System

Client: WS Atkins Rail Ltd.
Location: London to Glasgow, UK
Value: $8,700,000,000 (Construction)

In October 1999, a study of train protection systems on British main line railways was undertaken. One of the main issues studied was "signals passed at danger" (SPAD). It must be noted that a high speed passenger train will require approximately 2 km to come to a stop. In order to make this possible, the signal system provides two advance warnings in advance of encountering a red signal: a double yellow signal approximately 2 km from the red signal, and a single yellow signal 1 km from the red signal. The train driver has to heed these advance warnings and take into account the characteristics of his train performance and the physical characteristics of the railway line, (curves, grades, etc.) in order to safely stop his train as required.

Occasionally a train driver may misjudge the train braking performance or misread or miss a signal. This can result in his passing a Stop Signal. Although a majority of these incidents were found to cause no danger or accidents, a small portion (1%) lead to accidents, some with very serious consequences.

While driver training can cut down on the number of SPADs, additional forms of automatic protection was desired. After reviewing several options, the Train Protection and Warning System (TPWS) was chosen for nationwide implementation. A target date of December 2002 was enacted by the Government for complete implementation of the TPWS system.

The TPWS system will set the train brakes if the train passes a Stop Signal or if a train approaches a Stop Signal at excessive speed. The TPWS system is designed as an overlay to the existing signal system. The TPWS system was chosen over other proposals as a way to receive the maximum benefit in the shortest possible time. Other enhancements to the basic signal systems will be implemented in future years as the rail lines are upgraded.

GFT&RS has been selected to design the TPWS system for Britain's West Coast Main Line. This line extends 500 miles from London to Glasgow Scotland, via Rugby, Crewe, and Carlisle. GFT&RS will check all signal drawings as they are converted from hand drafting to CADD format, and will provide detailed circuit design and wiring plans for all TPWS locations.

The present signal system on the West Coast Main Line generally dates from the 1960s, and includes 78 major interlockings. In addition to the TPWS system, plans are underway to increase line speed from the current 90-110 mph to 125-140 mph. The cost of these improvements is estimated at 5.8 billion pounds.

GFT&RS is working for Railtrack, the owner of the British railway infrastructure, and WS Atkins, who is Railtrack's Program Manager for the West Coast Mainline Modernization Project.