Shunt Signals

well when a new signal is installed like the one at upminster reception road it is indeed a fibre optic type shunt and also around triangle sidings they also the newer type. but for the rest of them they will stay the mechanical type until they decide to re signal

refurbed as part of routine change no doubt if not just a new disc would of been installed i think they are changed every 18 years or is it 15 can never rememeber

The National Railway Museum claimed the last set of pneumatic signalling on the national network from Salisbury in 1981 so one would hope that the LT museum will do the same and claim some from the last installation on LT. I never realised that the LT ones were pneumatic. 'Puff and Dart' is alive and well!

for a LED to be replaced a safety Authroity to Work Certificate (AWC) has to be issued before it can be done. But LED's by themselves would not be installed during traffic hours as with tunnel type signal heads which have 2 bulbs in it the front bulb holder is usually blanked off and the LED is installed in the rear holder which would of been the MAIN lamp with the STANDBY at the front. I have noticed when doing jobs and I get a lift back with a Picc line driver between barons court and earls court the green is really green not the usual light green if you understand i dont know if they newer lenses or they just do a better job of cleaning them . But on SSL and BCV a bulb is never replaced with a LED in traffic. Tubylines might have different procedures but I'm sure that procedure has come from LUL's chief signalling engineer

On the Picc we were possibly the first line to switch to LED running signal lamps which must be 7 or 8 years ago now. I still don't know what the situation is with outside sections because at the time the LED lamps were unsuitable but certainly all the tunnel signal and repeater lamps were changed to LEDs soon after we changed all the trainstop Davis motors for the lighter Midland variety and all the WLs in the chairlock points to the new type. We were always very pro-active on the Picc in terms of remedial work and other work as that is what the Signal Manager liked, for instance fitting Norgren filters to all the EP valve lines in the Acton area. It was a nice interlude which broke up the routine signal maintenance module work. Policy was for every Picc TO to have a project or two on the go for those times when maintenance was up to date and we used to take on some installation tasks too. We routine changed an awful lot of 'Q' relays week on week too before the task was outsourced, of course this was pre-Tube Lines and things changed from 2002.

I am not surprised that the air main is set to go, I think this was quite evident when JLE was built with individual local area compressors. Of course LUs compressed air main was/is the large such distribution system in the world AFAIK and when it goes it will signal the end of an era. I don't think anyone can deny that LU has been well served by EP systems which have proved their worth over decades being used in so many diverse ways including such things as opening the old signal school car park gates at Earl's Court!

Like many things the air main is probably a victim of H&S requirements, presumably local compressors will still be required at all stations unless the UTS gates are going to change from EP to other operation.

Regulation, licensing, H&S, political correctness and the blame culture will in the end see the complete and utter demise of the railway that I enjoyed being a part of for almost three decades.

As for changing signal bulbs in traffic, surely as with all things signals the rule is still like for like replacement from a maintenance viewpoint so a defective LED would be replaced with another LED.
I agree that a bulb would not be replaced by a LED during traffic hours as it has to be checked for sighting.
Of course the days of changing signal bulbs in traffic are coming to a close too, the last I heard such practices were outlawed on JLE and the service staff would rather run trains under failure conditions and appropriate rules than allow linemen to work on the track even for a minute. I am told that no work would be permitted in the tunnels without discharging traction first so relamping signals is a no-no just as investigating and localising track failures is.

Station starters were being re-lamped on the JLE until a few months back, one was done at my station.

When the project staff went round and converted the lamps to LED's a email was sent to the service manager for each line involved. Most of the signals between earls court and Gloucester road are operated by 14v or 17v lamps (again xan't remember off top of head) and are mostly of the outdoor version of signal head they have 2 lenses one clear and one coloured these are known as Long Range Colour Light heads,and at the moment there is no LED suitable for these. At Acton Works they were playing around with LED's which replaced the lenses (like NR and traffic lights) but nothing has come around from this. The LED's currently what LUL have approved will only go in a tunnel type head/Short Range Colour Light head as these are also different as they are fed 100v. They could in theory put LED's in fog repeaters as these are just SRCL heads and are 100v fed but again the powers that be have declined possible because they would be alot brighter then the main running signal. So for signals in outside areas 98% of these would be normal lamps and not LED's

this is a outside signal head

www.trainweb.org/districtdave/assets/images/Sig_Head_with_Pigs_Ear.jpg

this is a tunnel type head

www.trainweb.org/districtdave/assets/images/Tunnel_Signal_Head.jpg

Hope Dave don't mind me using his pic ;D ;D ;D

We used to go out and change, optimally, four pairs of Q relays per shift on the section between Acton Town and Heathrow but it could be tough with the circuitry looping back and forth for hundreds of yards between several kiosks from a testing viewpoint and relatively short track time. But it was more interesting than some tasks despite the sore wrists (for those who don't know every contact has to be unscrewed to remove this type of Q relay and then screwed in to the replacement, about 35 screws per fully loaded single relay).

On the relamps there was only one signal that I refused to relamp and in fact it wasn't the signal itself but the harbour lights on WL25 at Acton. The signal is one of the tallest in the area and the fixed ladder ended beneath the signal head as do the majority but with little to hang on to with one hand one would need to stand on the top rung and still struggle to change a bulb halfway up the display board.

My recollection is that circa 2000 we did surveys of signals in open sections with a view to safety improvements. Following the surveys hoops were fitted to WL103C as a trial and safety harnesses issued. In some ways the hoops made relamping more precarious as they forced one to climb the ladder at an unnatural angle, the hoops themselves then becoming hazards to one's head!

I suspect that at some point most existing signals in open areas will be out of bounds in traffic hours pending improvements. Safest of all would be perhaps to be able to relamp at ground level so perhaps a switch to a different signal type will be the way to improve H&S for linemen.

I think that was inevitable really and no doubt there will be more meetings as H&S concerns are addressed further.
Funnily enough I had the gatso idea having watched them being worked on but realised almost immediately that there would be all sorts of complications. However, in the same vein, thinking about searchlight signals, roadside keep left lanterns and a little lateral thinking I had what I think is a much better idea;

Make the signal heads ground/low level units using either individual aspect LEDs or a newly designed single multi aspect LED cluster and instead of a load bearing signal post erect a strong but lightweight fibre optic light pipe with single aspect as required for appropriate sighting. It would be easier to install and could for instance be mounted directly above a signalling kiosk or form part of the standard signal location rather than requiring a separate concrete base, ladder etc etc. I appreciate that the post would need to be rigid enough and that sighting could be an issue too as a lightweight pipe might be subject to movement in the wind but there at least is the seed of an idea next time you are party to such discussions.

Tom you have a PM

No it isn't - it was decommissioned in April.

www.flickr.com/photos/signals/3476889841/