Signalling alterations

[whole diary]

[FarWestJohn]

I am sure there is an expert who can answer this for me.

On the up line on the approach to Dainton tunnel between Totnes and Newton Abbot there is a signal UM198. The distant for this, UM198R, was on a gantry giving good approach visibility. The gantry looks old and has been felled and is laying by the track. It has been replaced by a signal that can be no more than two feet from the ground.

I have never seen a running signal mounted this close to the ground where it could easily be obscured. It certainly looks odd.
The approach to UM198R is on a fairly sharp curve so the line of sight is not very good.

Does anyone know why this has been done?

[devon_metro]

Gantry collapsed onto the line, must be a short term fix. You can see the old gantry dumped down the line.

[signalandtelegraph]

It's actually UM218R.  It's original gantry was damaged by a road rail machine in a possession earlier this year and the structure was subsequently taken down.  At the moment, as you say ,the signal is mounted on a straight post but fairly low down I would assume that NR^» (Network Rail - home page) will eventually provide a new structure as the sighting on that stretch is particularly poor.  However if the drivers don't complain then they probably wont spend the money to do it.

[Tim]

It's actually UM218R.  It's original gantry was damaged by a road rail machine in a possession earlier this year and the structure was subsequently taken down.  At the moment, as you say ,the signal is mounted on a straight post but fairly low down I would assume that NR^» (Network Rail - home page) will eventually provide a new structure as the sighting on that stretch is particularly poor.  However if the drivers don't complain then they probably wont spend the money to do it.

surely they can't reduce ease of sighting a signal without it being spotted by a risk assessment?  Surely the paperwork required to (permanently) change a signals position would just be too much?  Surely the temporary solution is accompanied by a speed restruction or something to compensate for the difficulty in sighting?  Surely there is a more robust procedure than relying on drivers to report sighty problems?

[Zoe]

On the up line on the approach to Dainton tunnel between Totnes and Newton Abbot there is a signal UM198. The distant for this, UM198R

I didn't think repeaters were technically distants.

[eightf48544]

On the up line on the approach to Dainton tunnel between Totnes and Newton Abbot there is a signal UM198. The distant for this, UM198R

I didn't think repeaters were technically distants.

UM would tend to indicate these are auto signals, how many aspects do they have?

Repeaters are an anomaly in multi aspect areas. Take all the banner repeaters out of Padd on the Down main. They can only show if the signal is showing a proceed aspect. Thus if the previous signal is a Double Y then although the repeater for teh next siganl is off  you have to assumme the signal is showing Y and still continue showing down. Whereas it could be green. On an HST^▸ (High Speed Train) or Heathrow express you're locked down by ATP^▸ (Automatic Train Protection)  so there is no problem but on a Turbo.

So if the main signal is three aspect and the repeater is showing yellow you have to assumme that the main signal is at red. With a two aspect main signal there is no problem it acts like a distant, yellow main signal red, green main siganl green. 

However if the drivers don't complain then they probably wont spend the money to do it.

Surely they can't reduce ease of sighting a signal without it being spotted by a risk assessment?  Surely the paperwork required to (permanently) change a signals position would just be too much?  Surely the temporary solution is accompanied by a speed restruction or something to compensate for the difficulty in sighting?  Surely there is a more robust procedure than relying on drivers to report sighty problems?

Unfortunately it's one of the problems caused by the separation of track and train. In my day at Waterloo (early 60s) if there was any hint of dodgy signal sighting the local ASLEF^» (Associated Society of Locomotive Engineers and Firemen - about) rep  would be knocking on my govenor's door demanding a sighting committee. Especialy after a SPAD^▸ (Signal Passed At Danger).

[JayMac]

surely they can't reduce ease of sighting a signal without it being spotted by a risk assessment?  Surely the paperwork required to (permanently) change a signals position would just be too much?  Surely the temporary solution is accompanied by a speed restruction or something to compensate for the difficulty in sighting?  Surely there is a more robust procedure than relying on drivers to report sighty problems?

All of the above....and don't call me Shirley!!  (sorry, I know it's puerile, but I couldn't resist)

[super tm]

AIUI^▸ (as I understand it) the  system is  set up so that signal will never show red at the moment until properly fixed, so the sighting issue will not arise.

[gaf71]

AIUI^▸ (as I understand it) the  system is  set up so that signal will never show red at the moment until properly fixed, so the sighting issue will not arise.

A distant can never show a red aspect.

[super tm]

Yes but the issue is not with the distant which is on a gantry.  The associated stop signal on the floor is the problem and will not show a red aspect so the issue of poor signal sighting will not arise.

[Chris from Nailsea]

Sorry, but I was under the impression, from the original post here, that the cause for some concern is that the distant signal is no longer on a gantry? 

[devon_metro]

Correct Chris. It's on a very small post to the left of the up mainline on a blind left hand curve, hence why the raised gantry provided additional sighting.

[eightf48544]

Yes but the issue is not with the distant which is on a gantry.  The associated stop signal on the floor is the problem and will not show a red aspect so the issue of poor signal sighting will not arise.

If this is the case then presumably th headway is increased becuse you are effectively working double block.

Sorry, but I was under the impression, from the original post here, that the cause for some concern is that the distant signal is no longer on a gantry? 

I must admit from I reading  the original post and the subsequent correction of the signal number that it was a reapter/distant UM 218R. Which makes sense as the SW end Dainton tunnel is at miles 217 64 chains. 218 in the siganl nmber being the mileage. Milage 198 is around Exminister.

[FarWestJohn]

Yes, my fault, I started the thread and it is UM 218R tied in with the mileage.

I assumed that this was a two aspect distant auto for UM218 so the sighting distance would be fairly important even though the normal train speed at this point is not very high.

I will have to look again next time I pass.

Thanks for all the comments.