6 key considerations in determining suitability of permanent Track Warning Systems (TWS)

Schweizer Electronic have launched a white paper aimed at exploring the difficulties Rail maintenance teams face in attaining the highest level of Safe System of Work (SSOW) under the pressures of increasing train traffic, and proposes a permanent Track Warning System (TWS) as a possible solution to the challenges of obtaining track access.

As rail passenger numbers and levels of freight increase across Europe and the rest of the World, some rail infrastructure companies find themselves in a ‘Catch-22’ situation - squeezing more trains onto the network with less time to close the track to adequately maintain it. All this is made more difficult under a tighter regime of Safe System of Work Planning (SSOW) and optimising the level of protection to the workgroup.

Schweizer’s white paper explains how permanent Fixed Automatic Track Warning Systems (FATWS), Semi Automatic Track Warning Systems (SATWS) or Signal Controlled Warning Systems (SCWS) can provide valuable forms of red zone protection for areas of the track where repeated planned or unplanned P-way maintenance activities take place. As well as 24/7 access, these systems offer manpower savings over other forms of protection, and have the added benefit of providing a favourable business case.

To assess a site for suitability for a permanent TWS, rail infrastructure need to make 6 key considerations:

1. How busy is the track?

Maintenance teams will know the places where they struggle to get possessions, not only for longer blocks but even short possessions in some cases.

2. How many man hours per week are spent maintaining/protecting it?

It is useful to analyse and total how often workgroups are going to the same locations on the track for P-way activities and how many additional protection staff are required. Is access required 24/7, or can it be left for quieter times of the week?

3. What type of work is taking place?

There is a significant amount of regular activities across all the disciplines which could benefit financially from this level of SSOW. When assessing a list of maintenance activities consider whether maintenance work is planned, or can be anticipated as requiring a SSOW from the evidence of past failure data.

4. What’s the most difficult topology of track maintained by the depot?

Consider which areas of the track are notoriously difficult to protect in a Red zone. For instance a busy junction, with 2 or more routes merging can require several traditional or LOWS lookouts to provide adequate warning. Reverse curves may require assisted lookouts, and radio reception for LOWS could be affected by deep cuttings.

5. Can you build a business case?

Use the information gathered so far to structure a favourable business case and payback calculation. Moreover consider if permanent TWS can improve performance reliability and journey times for passenger and freight services, providing longer term revenue improvement for the Rail Infrastructure Company.

6. What technology is available to provide a solution?

When selecting a permanent TWS solution it is important to consider whether the technology is reliable and has the capability of managing the complexity of track. An assessment of the manufacturer’s history is also crucial to judge their expertise in work protection and long term permanent TWS sites.

To download a copy of the white paper, access Schweizer Electronic’s website at:


With over 45 years of experience, Schweizer Electronic provides temporary and fixed Track Warning Systems (TWS) which improve safety and access to running rail in a red zone environment. Approved for use in many countries across the World, its track worker protection systems use failsafe SIL3 accredited technology which can be configured for most worksites.

For more information, view our website at


To contact us call 01827 289996 or email at

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On its stand B130, Schweizer Electronic will be exhibiting at this year’s Railtex at London’s Earls Court on 14-16 June 2011. At the show Schweizer plans to display its new Lookout Operated Warning System (LOWS), permanent Automatic Warning Systems (ATWS), a Train Emergency stop and its level crossing system, Flex.

‘This is the first time we’ve exhibited at Railtex’ said Chris Foreman, General Manager of Schweizer Electronic UK ‘we really wanted to show visitors our product range, developed with the type of safety and track access issues rail maintenance and construction teams are facing at the moment’

From its headquarters in Switzerland, Schweizer Electronic’s new Lookout Operated Warning System (LOWS) has been built to provide a flexible warning device, portable for maintenance patrolling whilst also capable of setting up a temporary semi automatic track warning system in plain line work sites. For maintenance delivery teams where higher safety levels for track workers and 24/7 track access is becoming challenging under a 7 day railway and increasing traffic, Schweizer Electronic are now introducing the permanent installation of Minimel 95 ATWS onto the rail network.

Since adjacent open line working is becoming more of an imperative to prevent passenger disruption, Schweizer Electronic are now working on an Emergency Stop system to prevent the risk of collision between road rail excavators, track machinery and trains. The system which is integrated into the ATWS utilises a mobile TPWS, circuit breakers and temporary red signals.

Also from its stand, Schweizer Electronic plan to exhibit its FLEX railway crossing. This provides a safe and affordable crossing system which is scalable from small rural user worked crossings to complex multi barrier systems. It is made up of familiar, extremely reliable industrial components and equipped with market-leading LED and wheel sensor technology.

Schweizer Electronic UK provides Automatic Track Warning Systems (ATWS) and Lookout Operated Warning Systems (LOWS) which improve safety and access to running rail in a red zone environment. Its track worker protection systems have a minimum SIL3 rating and are only used under approval from Network Rail. Schweizer Electronic supports a group of nationwide partners who offer planning, installation and operation services for ATWS and LOWS.