LED 4 aspect signals

[SouthStand]

IIRC i'm sure the signal on the down slow at East Midlands Parkway would be at almost ground level, yet the restrictive aspects are shown on the lower lens. Of course, I'll be damned if I can find a picture!

e: https://www.youtube.com/watch?v=O4e0NATqJXg at about 3:15 ish.

Sure the aspect ratio on that video appears wrong?

 

[ac6000cw]

Sure the aspect ratio on that video appears wrong?

Not my video, but yes it's wrong (it's been shot in 16:9 but encoded as if it's 4:3), but that doesn't affect what's being discussed here.

 

[Railsigns]

I'm not sure how Approach Lit fits in with Detection of the aspect showing.

Where approach lighting is employed on Network Rail, lamp proving operates as normal. That is, when a route is set towards an approach lit signal it is then supposed to illuminate but if it fails to do so, the signal at the entrance to the route will remain at red. Also, a contact of the approach lighting relay is included in the filament failure circuit to suppress any alarms while the signal is legitimately extinguished.

 

[Taunton]

Where approach lighting is employed on Network Rail.

So there's another question, because I can't recall seeing this still in use anywhere in Britain.

 

[Railsigns]

So there's another question, because I can't recall seeing this still in use anywhere in Britain.

Approach lit signals on NR are almost exclusively confined to Scotland, where there are about thirty-five currently in use. There is also one at Haresfield, near Gloucester.

 

[Taunton]

Seeing as a opening topic of LED signals has gone down the road of Searchlights, sort of related as they both show multiple colours through one lens, we can mention in passing a few more variations.

The LMS put in two one-off signal systems using these units. One was the Mirfield Speed Signalling near Huddersfield, covering a few miles of a busy main line, and was based entirely on US practice with four or more searchlight units per signal post which displayed a whole variety of colour combinations to indicate speed and route. There's one in York Museum. I believe the whole installation used imported US components from one of the two major US signal manufacturers.

http://www.signalbox.org/signals/lmsspeed.htm

It was put in about 1930 and replaced by conventional 4-aspects about 1970. I wonder if anyone here ever operated there when they were in use; what sort of training needed to be given.

Another LMS scheme was on the Euston-Watford DC Line, which must have held the record for the number of signals per mile it required, many were little more than a train length apart, but it did allow a very frequent service of both LMS and Bakerloo Line trains which shared the route. It had some common features with Mirfield, with multiple searchlights on one post.

The GWR resignalled a number of major areas (Paddington to Slough, Bristol etc) in the 1930s with Searchlights, which just duplicated what was seen on semaphore signals at night, so a 2-aspect Searchlight red/green was above one that did yellow/green, just like a home/distant on one post. A difference was that the GWR did a whole area, whereas the LNER, and to a lesser extent the LMS, tended to do just individual signals, especially distants and IBS, with Searchlights.

If the Southern ever used Searchlights it would be interesting to hear of it. They were the pioneers of four-aspect signals, the earliest of which were set in a diamond pattern in a circular shield, later moving on to the current vertical orientation.

 

[Railsigns]

If the Southern ever used Searchlights it would be interesting to hear of it. They were the pioneers of four-aspect signals, the earliest of which were set in a diamond pattern in a circular shield, later moving on to the current vertical orientation.

The vertical type signals were used right from the beginning, along with the 'cluster' signals. If you look at the Southern Railway's earliest four-aspect signalling schemes, you'll see both types. Cluster signals were specifically intended to be used on gantries, where there was a concern that the lens hoods might obscure the driver's view of the aspects when the train was stopped close to the signal.

 

[edwin_m]

A difference was that the GWR did a whole area, whereas the LNER, and to a lesser extent the LMS, tended to do just individual signals, especially distants and IBS, with Searchlights.

I believe the LNER did instigate some whole-area signalling schemes, for example on the ECML between York and Tyneside and on the GE, and all using searchlights. Some of them may have been put on hold by WW2 and only completed after nationalisation.

I'm not aware of any whole-area LMS schemes other than Mirfield and Euston-Watford, but no doubt someone will be along soon to advise. They did do a lot of replacement of semaphore distants with colour lights (often moving it further out for higher speeds at the same time) but weren't these mainly of the multi-lens type?