RAIB - incident at Stainforth Road near Doncaster

[John Webb]

Posted on the RAIB website today:

At about 05:45 hrs on Thursday 11 January 2018, a car collided with a freight train which was standing on the down Skellow line with its rear wagon partially blocking Stainforth Road automatic half-barrier (AHB) level crossing. The car driver suffered minor injuries in the collision and their car was severely damaged.

Despite the presence of the train at the crossing, Stainforth Road AHB level crossing was open to road traffic when the collision occurred. This meant that its road traffic signals were not illuminated and its half-barriers were in the up position. At the time the accident occurred it was dark. The crossing is not illuminated and its rural location means that there are no ambient light sources nearby.

The design of this crossing results in the requirement for down trains to cover a distance of around 28 metres to clear the road surface after the re-opening sequence has been triggered. For trains travelling close to the maximum permitted line speed of 50 mph (80km/h), the time needed to clear the crossing is well within the approximately seven seconds required for the re-opening sequence to be completed. However, for trains travelling at very slow speeds, or where trains stop with the rear wagon close to the crossing and blocking the road, the crossing can potentially re-open to road users while such a train is still on it.

Our investigation into the accident will determine the sequence of events leading to the collision. It will also include consideration of:
•the design of this level crossing and relevant risks associated with it
•whether similar designs are in use at other locations
•the actions of the railway staff involved in the operation of the train
•any underlying management factors

Our investigation is independent of any investigation by the railway industry, the British Transport Police or by the industry’s regulator, the Office of Rail and Road.

We will publish our findings, including any recommendations to improve safety, at the conclusion of our investigation. This report will be available on our website.

[JG Morgan]

I am not familiar with this location, but my observations suggest that the situation / operation described may not be unique to that location.
1) At various crossings on the Nottingham trams (NET) the road traffic lights change to green while a tram is still crossing the road, before the back end of the tram is clear.
2) I recall seeing a picture in Modern Railways showing a Triumph Spitfire or similar sporty car being driven under the nose cone of an HST stopped partly across a level crossing. This was somewhere on the Berks & Hants Line, probably early 1980s. The HST was stopped either at a station or at a signal after the crossing; it had cleared the track circuit or other detection, such that the barriers opened even though the back end of the train was partly across the road.

As in all cases, we await the RAIB's report with interest.

[Signal-sighter]

I'm aware of a not dissimilar incident a couple of years ago (where a collision with an unlit freight wagon on a timed-out crossing was narrowly avoided by the actions of a road user) which RAIB asked some pretty probing questions about but ultimately did not conduct a full investigation. It'll be interesting to see if it gets a mention in the report for this occurrence.

[Danny252]

I'm intrigued by the description of the crossing's operation from the RAIB brief. Should this be taken to mean that AHBs are not provided with a track circuit (or axle counter section) over the crossing itself, which forces the operation of the crossing when occupied, regardless of the normal approach sequence?

[BHornsey]

This is quite common with the AHBs I've worked with. We've had numerous WSFs reported at these crossings (a train on the crossing with barriers up) over the years and further investigations have always revealed that the road user has approached the crossing with the train (in nearly all cases running slowly) already on the crossing.

In fact I recall some of the MCBs on the Liverpool Street division, where I worked many years back, could be raised with the back of a train on the crossing.

[Mad Mac]

Basically, there are two track circuits, and the barriers come up after the “approach” one clears. The assumption is that the train is moving at a speed whereby it will clear the crossing before the lights go out. Us crossings have a separate “island” track circuit which covers the roadway and keeps the crossing activated.

[Ben.A.98]

We have middle tracks on our AHBs in Scotland.

[Mike Hodgson]

I'm intrigued by the description of the crossing's operation from the RAIB brief. Should this be taken to mean that AHBs are not provided with a track circuit (or axle counter section) over the crossing itself, which forces the operation of the crossing when occupied, regardless of the normal approach sequence?

The IRSE's Railway Control Systems published in 1991 gives typical circuits for AHBs (and other types of crossing then current) - fig 6.5 & 6.6 & 6.11 & 6.12 for double line bi-directions strike ins. These do show short track circuits for the crossings, but a note says these are only provided for specific risks - notably agricultural vehicles occupying and short circuiting the track circuit causing the crossing to fail. Where they are not provided the strike in TC extends to include the crossing.

Fig 6.10 also shows a separate short TC for the crossing for single lines, but of course for trains running the other way the strike-in TC becomes the strike-out and vice versa. Single track may in part explain why middle tracks are more common in Scotland.

I don't know if this logic is still valid as most track laying vehicles I have seen lately seem to have rubber tracks rather than the chain-link tank type tracks which seemed more common when I was young. However, there may well still be places where this is an issue.

[John Webb]

I am uncertain how snow in particular lying on a railway line can affect track circuits. To what degree would snow hit with salt/grit mix be likely to cause problems with track circuits across a level crossing, as a saline solution is rather more conductive than plain water?

[Mark Lamb]

On the older types of AHB crossings - of which Stainforth Road appears to be one, by virtue of the 'penguin' barrier machines - there was usually only one track circuit in each direction. This extended from the strike-in point to just short of the crossing. The barriers were raised by operation of an exit treadle on the opposite side of the crossing and with the track circuit clear, therefore it is possible for a train to be obstructing the crossing with the barriers raised.

There were two main reasons for this: 1) simplicity of design using as few pieces of equipment as possible (thus reducing the failure possibilities), and 2) if the track circuit extended across the roadway, the barriers may be operated by a tracked, slow vehicle. This could conceivably be trapped by the descending barrier. This wouldn't stop a train correctly striking-in, with the possibility of a collision occurring.

As far as I know, there are still quite a few of these about as the renewal of these to modern standards isn't easy! (Reason 1 above doesn't apply today). The principle of track circuits stopping short of the roadway applies to other crossings too, such as Traincrew-Operated barriers.

'New' AHB's tend to have three track circuits per line - a strike-in for normal and wrong direction, and an island track circuit across the road. Occupation of the island track won't initiate the crossing, therefore the collision risk is removed.

Regards,

Mark