Facing point locks

[JoeGJ1984]

I know that facing point locks are used to prevent points moving while being traversed in the facing direction, but in sidings, depots, etc. FPLs are usually not fitted. How then, with an ECS or light engine movement in the sidings, the FPL is not needed? All right, there are no passengers but still I thought the train could derail if the points moved under it in the facing direction.

 

[carriageline]

Yes they can, but I guess as the speed is normally lower, and the risk to life is minimal (as only rail staff should be on board! ) the cost of fitting them outweighs the chance of trains derailing.


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[driver9000]

Most points in sidings and depots are hand worked points so an FPL wouldn't be able to be fitted. The speed is only 5mph at most too, true there have been derailments over hand worked points but an FPL isn't necessary and would no doubt slow work in the yards down if FPLs were unlocked and locked each time the points were to be moved. Pointwork out onto running lines at the yard I work out of with mechanical points do have FPLs fitted though.

 

[w0033944]

I'd imagine that the reasons as already provided would also apply to the question of why fully interlocked signalling working on absolute block or a form of automatic block isn't used in depots and sidings; extra complication and expense for little benefit.

 

[dysonsphere]

I dont think freight lines require FPL either one of the problems with running passengers over freight only line in an emergancy. I think if that happens points have to be clipped.

 

[LowLevel]

If there's points with a signal over them then non passenger or trailing points will be detected by the signal mechanically in the case of semaphores - ie if the points aren't over far enough, the detection will not physically allow the signal to clear. However it's not considered substantial enough for a passenger service hence the use of a facing point lock to provide a more solid locking mechanism. Point detection is generally more than enough to stop the points moving under a train though.

 

[edwin_m]

Although facing point locks (and various other signalling features) aren't required on goods lines, many would have had them because either they were previously passenger lines or they were maintained to passenger standards to allow diversions.

All point machines include a facing point lock as standard so power-worked points have one whether facing or trailing and whether on a passenger line or not.

 

[carriageline]

We have clamplock points (so not quite power!) which don't have FPLs


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[Railsigns]

We have clamplock points (so not quite power!) which don't have FPLs

All clamp lock points have FPLs; they just aren't in the traditional form.

There are still a few electric point machines around which do not incorporate an in-built FPL.

 

[MarkyT]

Board of Trade, later Railway Inspectorate rules required facing points on passenger lines to be fitted with a FPL device, originally operated by a separate mechanical lever in the signal box or ground frame, but later in some designs operated along with the switch rails by the same lever and a cam arrangement, the "economical facing point lock" (EFPL) concept illustrated here:

http://www.rmweb.co.uk/community/uploads/monthly_05_2014/post-9767-0-51119700-1399413522.jpg

Some early designs of electrical point machine used a similar cam concept like the EFPL, whilst others were available in two options, with or without a separate FPL mechanism, although I doubt any without FPLs survive on NR infrastructure.

The clamp mechanism in a clamp lock point is considered to provide equivalent security as a conventional FPL arrangement.

 

[carriageline]

All clamp lock points have FPLs; they just aren't in the traditional form.



There are still a few electric point machines around which do not incorporate an in-built FPL.

How comes our SBSI state they are NOT fitted with the equivalent to a facing point lock then? Genuine question


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[Railsigns]

How comes our SBSI state they are NOT fitted with the equivalent to a facing point lock then? Genuine question

I genuinely don't know. Are they definitely clamp locks? If you can say where they are, then maybe I can investigate.

 

[carriageline]

I genuinely don't know. Are they definitely clamp locks? If you can say where they are, then maybe I can investigate.

You have PM


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[Philip C]

I've had a question hanging around at the back of my mind for a very long time and wonder if anyone can answer it for me?

Until the early 1980s I travelled on a regular basis from West Worthing towards London. At that time the "depot" at West Worthing was still in use and a few trains came into service from it. Some of these trains were of twelve car length and, as the up platform took little more than four carriages, the rear of the train had yet to pass over the depot outlet point (a double slip I believe). By rapidly moving down the train it was possible to get beyond this point before the train moved off.

I often wondered if there was an FPL on those points. Does anyone know?

At the time I resisted the temptation to ask as, had the the FPL not existed, an obvious remedy would have been to start the train for passenger purposes at Worthing Central thus causing me, and others, considerable inconvenience!

 

[MarkyT]

I often wondered if there was an FPL on those points. Does anyone know?

I'm not sure of the dates of the resignalling around there. Assuming electric point machines controlled from Lancing as now, I would expect there to be a built-in FPL for the siding trap points (part of the double slip). Any previous local mechanical signal box controlling the same layout at West Worthing would almost certainly not have had such a feature.

 

[oddiesjack]

When we occasionally get railtours visiting Buxton, they generally arrive via the old Midland route, and into "Donnaroo" sidings - effectively the headshunt for trains going from and to the Hindlow branch, with a line into Buxton station. The points in the sidings are not fitted with FPLs, and so these have to clipped when the train is reversed into Buxton station. The Hindlow limestone trains suffer no such delays.

 

[andyb2706]

Apologies if some one has already said this but basically you answered your own question.

FPL do not need to be fitted on points where passenger trains do not normally travel through them. That is why when rail tours take in lines that are not normally travelled by passenger trains a competent railway employee has to attend and manually secure the points for the safe passage of the passenger train.