Pedicting the future of level crossings

Much has been written, not least in these pages, about safety at level crossings. Any interface between people and moving trains is inherently risky, with both pedestrians and vehicle drivers sometimes prepared to take a chance, occasionally with disastrous results.

Naturally, there have been many meetings devoted to the topic. Back in 2002, there were extensive discussions involving Invensys, Network Rail and the Office of Rail Regulation (ORR) to identify the main causes of level crossing accidents and to develop improvements to the infrastructure. One of the main causes of accidents was identified as the varying time between barriers closing and the train arriving – in particular it seemed that, at Automatic Half Barrier (AHB) and User Worked Crossing (UWC) sites, users were much more prepared to take risks.

As a result of these talks, Invensys focused on the Level Crossing Predictor solution that was in use elsewhere within the Invensys Rail group, particularly the WESTeX GCP3000 system which can be overlaid onto existing infrastructure and which provides consistent warning times.

Well established principle

While new to the UK, the Invensys Rail WESTeX Level Crossing Predictor (LCP) system had been in operation in the United States since the mid-1960s, with tens of thousands of the system in successful use across the USA, Australia and New Zealand.

The basic principle of the predictor is that, once an approaching train has travelled over a shunt, the system calculates the speed of the train and therefore the point at which it will arrive at the level crossing. By calculating the speed of the train, the GCP3000 is able to provide a consistent, pre-determined warning time for each train regardless of its approaching speed, minimising disruption to road users and significantly reducing the risk of crossing abuse.

Once the train has passed over the level crossing, the sequence to re-open the crossing to users is initiated – the train is monitored until it has passed over the termination shunt, ensuring that the same level of bi-directional functionality is provided as with a conventional system. The predictor typically requires just a single unit at the crossing itself, together with passive termination shunts between the rails at the strike-in point.

Both Network Rail and the ORR saw this as a potential solution. The GCP3000 system successfully passed through the product acceptance process in 2009 for all types of level crossing on non-electrified infrastructure, covering both AHB and UWC installations.

Initial trials

A number of UWC trial sites were installed in England and Northern Ireland, covering a range of configurations, including those featuring stations on the approach. In 2011 a further eight UWC sites were installed across the UK, each of which is now in full operational service.

In March 2012, the first GCP3000 AHB application was commissioned at Cherry Holt by a third-party provider. The system was interfaced with standard 24v Dorman road traffic lights and conventional type BR843 barrier machines. During the trial, an incident occurred due to poor rail shunting with a light locomotive on rusty rails. The level crossing predictor system, however, behaved exactly as expected by providing a warning that, although shorter than normally expected, still brought the barriers to the lowered position despite the intermittent rail shunting. During the investigation, the system remained in full operational service as the inspection report was very positive about predictor technology.

More recently, a GCP3000 system has been installed at West Bank Hall on the Drax line, and a further five AHB systems will be delivered as part of the third tranche of the level crossing programme.

Effectively now offered as an”off-the-shelf” solution, the GCP3000 is suitable for use on Miniature Stop Light (MSL), AHB and Automatic Barrier Crossing, Locally-monitored (ABCL) applications. For example, at sites such as Tinsley EUWC, which has a standard up and down line with no track circuits and a 70mph maximum speed limit, it offers a good solution with all the equipment fitting in a standard location case.

Diagnostics

The GCP3000 also provides operators with a full diagnostics capability. It monitors the condition of the railway throughout the area covered by the crossing strike-in and advises the maintainer if there is a problem with the infrastructure, and where that problem is on the track.

The Invensys Rail technical support team recently worked with a Network Rail maintenance team which had reported a problem during the re-linearising of a level crossing following a re-rail exercise. Using remote diagnostics, the Invensys team identified an area of poor rail condition which coincided with the re-rail. The site team subsequently discovered that a small area of the new rail was slightly corroded. Once cleaned, the new rail and the level crossing were successfully brought into service.

When a level crossing is equipped with a modem, the Invensys team and the maintainer both have dial-in diagnostic capability for any issue within the strike area. Now that the GCP3000 system has been certified, technical support for all first line technical issues is passing from the company’s York office (where the WESTeX development team is based) to its central aftermarket support team in Chippenham. As part of this process, new technical manuals are also currently being developed, in conjunction with Network Rail, to ensure they are complete from a maintainer’s, designer’s and installer’s perspective.

Lightweight barriers

In addition to the predictor systems, the WESTeX range also includes the lightweight S60 barrier machine, which in June 2012 received a certificate of acceptance from Network Rail for use at MCB and AHB level crossings. Examples of the S60 will be installed in the UK as part of the Crewe – Shrewsbury modular signalling project, with sixteen machines being installed at Manually Controlled Barrier (MCB) crossings which are being converted to MCB with Object Detection (OD) – consequently, the barriers are being supplied fully fitted with skirts. In line with Network Rail’s modular ethos, the S60 machines are being built and tested off-site at Invensys Rail’s facility at Chippenham prior to being delivered for installation and commissioning.

The S60 barrier machine is an electro-mechanical product rather than a traditional hydraulic system, making it far simpler to operate and to maintain. Available in a range of configurations, the machine uses less power and requires a smaller equipment housing and footprint than conventional systems. The post on which the S60 is fixed is also able to mount the road traffic lights. With a balanced weight distribution, it can use a screw-pile foundation, offering the potential for both installation time and cost savings.

Future developments

The next generation GCP4000 Level Crossing Predictor system has recently been introduced to the UK. An advanced predictor and solid state crossing control system, the GCP4000 delivers all the capability of the GCP3000 system but with the addition of a level crossing controller enabling direct control of 12 volt road traffic lights and the Invensys S60 barrier machines. It also incorporates additional functionality enabling it to control more complex infrastructure, while reducing the number of external timers and relays and therefore the REB requirement and the cost of civils work.

Trials of the GCP4000 have been completed at High Scampston on the York to Scarborough line in shadow mode, successfully demonstrating that the barrier-down time is reduced through the use of the predictor. In line with Invensys Rail’s modular solution, standard GCP4000 designs have now been templated, meaning that site-specific data needs only to be added for each new application. Consequently, the unit may be tested off-site, reducing cost.

Two other current projects address issues with UWCs. The first covers the lack of a suitable (110V) power supply in remote locations, with the company working to develop solar and wind-powered options. The team is currently seeking product acceptance for a number of systems. The second project is addressing the issue of the misuse of UWCs, particularly gates being left open.

Invensys has implemented a level crossing in Scotland where security key fobs have been assigned to the principle user, with a push-button system for infrequent users. This trial has led to a 95% reduction in misuse.

Introducing this technology forms part of Network Rail’s ongoing initiative to make crossings safer – which is already showing positive results.

One Response to "Pedicting the future of level crossings"

  1. Sbsatish Bilgaiyan59 says:

    Very happy to know about the sucesses of GCP3000 as reducing power, no. of relays etc. Congratulations to the York office design team.

    Reply

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