Single Lens Signals

[Yank 119]

I'm curious about the single lens signals I've seen in photos throughout the network.

Popularly known as searchlight signals here in the US, these neat devices are gradually being replaced in favor of less maintenance intensive tri-lens signals. Many of them date back to the 1940s, which is fair reason for replacement. They are still in widespread use (and were once the standard) in Canada, however.

I've noted that in Britain, many new LED single lens signals are popping up in various places. I'm also aware of the older incandescent signals on the GWML outside of Paddington, presumably installed as a result of the Ladbroke Grove incident.

My questions are:
Where are these being installed, and what are the reasons for their installation? Are they becoming "standard?"

Who are the manufacturers of the hardware?

Thanks for tickling my curiosity. Links to photos are always welcomed.

Joe
Statesboro, Georgia

http://www.railpictures.net/viewphoto.php?id=204157 <<< An example of searchlights in the US

 

[bluenoxid]

I dont know the exact reason why, but I believe it is due to them being cheaper and easier to maintain as they are a standard type, last longer and are easier to duplicate. They are also more powerful and are less likely to suffer from water in the lens

 

[thelem]

Can you provide a picture of a tri-lens signal, as from the above it sounds like a signal with one lens that changes colour, but that would not work for drivers who were colour blind.

 

[djw1981]

IIRC colour blindness prevents one becoming a driver. Happy to be corrected though.

 

[Yank 119]

Can you provide a picture of a tri-lens signal, as from the above it sounds like a signal with one lens that changes colour, but that would not work for drivers who were colour blind.

Tri-lens signal examples:
UK
US

Single lens signal examples:
UK
US

And yes, single lenses may pose a problem to colour blind drivers. I guess there can't be any colour blind drivers...

An interesting website regarding North American searchlight signals

 

[jv3531]

One of the reasons is that they provide a clearer more definitive colour and increase signal sighting. It also reduces the risk of cross reading in direct sunlight where on the old signals it could be taken as a red stop showing a yellow caution aspect. As there is only one or two to replace a 4 aspect, confusion is removed. They are also capable of displaying flashing LEDs if required on high speed routes/junctions.

 

[TDK]

I'm curious about the single lens signals I've seen in photos throughout the network.

Popularly known as searchlight signals here in the US, these neat devices are gradually being replaced in favor of less maintenance intensive tri-lens signals. Many of them date back to the 1940s, which is fair reason for replacement. They are still in widespread use (and were once the standard) in Canada, however.

I've noted that in Britain, many new LED single lens signals are popping up in various places. I'm also aware of the older incandescent signals on the GWML outside of Paddington, presumably installed as a result of the Ladbroke Grove incident.

My questions are:
Where are these being installed, and what are the reasons for their installation? Are they becoming "standard?"

Who are the manufacturers of the hardware?

Thanks for tickling my curiosity. Links to photos are always welcomed.

Joe
Statesboro, Georgia

http://www.railpictures.net/viewphoto.php?id=204157 <<< An example of searchlights in the US

The single lens signals are being installed as replacement for the traditional 3 aspect signalling. They can display whatever the old signals displayed. They do not actually have a lens but they are LED signals. They are made by Dorman and generally installed in conjunction with axle counters. They are on the below routes (as far as my route knowledge can remember)

Telford to Oxley
Crewe to Stafford (4 aspect, 2 for LED)
Birmingham international to Coventry (4 aspect 2 for LED)
Small heath Jct to Leamington Spa (4 aspect 2 for LED)
Coventry to Leamington Spa
On the Chester to Holyhead line (small number)
Crewe coal yard to Weaver Junction (4 aspect 2 LED)

A different type has been installed between Crewe and Manchester Picadilly these are made by Ensaldo and have lenses but use the same principle as the Dormans. These are 4 aspect signalling with 2 lenses.

Where these signals have been installed there are axle counters and not TCB and in most cases IVRS is used in these areas (except Telford to Oxley and Crewe to Manchester)

Hope this helps

 

[Barn]

IIRC colour blindness prevents one becoming a driver. Happy to be corrected though.

I would hope you're right. Think about night time when you wouldn't see the positioning of the lamp - you'd just see the colour.

 

[me123]

Pretty sure that that is the case; I know someone who wanted to work at a station (as dispatch staff) a few years back and was rejected because of colour blindness. I certainily wouldn't want a colour-blind driver!

 

[laseandre]

They have also been installed at Glasgow Central.

 

[bunnahabhain]

http://www.gcrailway.fpic.co.uk/p26597900.html

LNER Mechanical Searchlight signal there, unique these days.

 

[Metroland]

LED signals are the new standard. For a start is saves changing over the SL-35 (12v 35watt) double filament bulbs of older multi-unit signals. There are various manufacturers, such as

http://www.vmslimited.co.uk/rail.html

 

[Snapper]

Here's a selection of UK single-lens signals and LED signals, some of which are of an older design which has now been displaced:

http://www.paulbigland.fotopic.net/p8369635.html

http://www.paulbigland.fotopic.net/p30705394.html

http://www.paulbigland.fotopic.net/p49460868.html

Here's the Ansaldo design:

http://www.paulbigland.fotopic.net/p48189724.html

And the Dorman design:

http://www.paulbigland.fotopic.net/p48388116.html

 

[AlexS]

Also installed Nuneaton to Wigston North Junction.

They're far more reliable than the traditional bulbs and brighter too - a colleague on the S&T told me that they haven't had a single failure of aspect that was as a result of the signal LEDs themselves in 10 years, anywhere, which is the time period before the LEDs are renewed.

 

[Yank 119]

Here's a selection of UK single-lens signals and LED signals, some of which are of an older design which has now been displaced

Thank you very much! I've been looking at your site on and off for the past couple of days, but I did not dig deep enough to find those photos you linked.

Great photos and thanks for the info.

 

[furryfeet]

LED singnals are also being installed in the trent valley as part of tv4 as i write.

who is the manufacturer in this case ?

 

[me123]

I think Dundee now has them too. They're also at Edinburgh since resignalling and obviously the new SAK railway.

LEDs are very clear compared to the traditional signals IMO, though. They come up much brighter and I'm sure they're easier to see, even in bright light. At GLC, they do make a difference.

 

[kestrel]

I would hope you're right. Think about night time when you wouldn't see the positioning of the lamp - you'd just see the colour.

If you're colour blind you won't be allowed to drive trains or despatch them
--- old post above --- --- new post below ---
The single lens type signals were installed in paddington throat following the Ladbroke grove accident to make the signals clearer to see, they use Fibre obtic technology with the light source being mounted in a cabinet on the gantry,
All of these however are in the process of being replaced with LED signals to aid signal sighting, SN63 being a particular signal with known sighting problems and additional solutions to this one are being sought.

There are advantages using LEDs they use less power, last longer and are much clearer to see than 'filiment' types.

 

[Jordy]

The LED style ones seem to be cropping up everywhere, some have even appeared at Grimsby!

 

[O L Leigh]

We have a few LED's too. They are dazzlingly bright, even more than the former standard signals with incandescent bulbs (and they are pretty damn bright). The "related" signal inside the Airport Tunnel for "Up" trains is now an LED, but it's just way too much for the setting. I take the aspect from the reflection off the tunnel walls and then look away when the signal itself comes into view to reduce the effect of dazzle on my vision.

The other problem with LED's is that you tend to lose the aspect as you get right up to it because they are very directional. The designers get around this by fitting a "fringe" of a different type of LED that are less directional so you can still see the aspect. On the downside it's not so obvious as it would have been with an incandescent.

O L Leigh

 

[robvulpes]

LED signals are the new standard. For a start is saves changing over the SL-35 (12v 35watt) double filament bulbs of older multi-unit signals. There are various manufacturers, such as

http://www.vmslimited.co.uk/rail.html

Have any of THIS design been installed on NR? All the LED signals I've seen have been of the type where all the colours are put through a single final 'lens' (or 2 for 4-aspect signalling), rather than separate single-colour outputs.

AIUI ('Modern Railways' article at the time??), despite being recent, the Portsmouth resignalling used incandescent bulbs.

Round my way (Brighton main line), there has been patch replacement of a few ~25yo signal heads with the 2-lens for 4-aspect LED variety. On that type, is it true that the upper lens can also display more than just amber (e.g. as a back-up red if the bottom red goes wrong)?



Rob

 

[Dougman]

I think Dundee now has them too. They're also at Edinburgh since resignalling and obviously the new SAK railway.

LEDs are very clear compared to the traditional signals IMO, though. They come up much brighter and I'm sure they're easier to see, even in bright light. At GLC, they do make a difference.

Dundee has LED ground signals and call on signals, however the main running signals are still incandescent bulbs.

 

[class 313]

Farringdon station now has a one light signal facing towards Snow Hill Tunnel.

 

[First class]

They're now between Huyton & St. Helens Jn in Merseyside in both directions. Interestingly, an extremely busy commuter line from Huyton-Wigan, Preston & Blackpool still has some semaphore signals in the merseyside area...

 

[driver9000]

the LED signals on the Chat Moss between Huyton & Rainhill etc were installed when that line was resignalled to abolish the Absolute Block method of work along that line. The St. Helens lines between Huyton & St Helens Central is still signalled under Absolute Block however the only semaphores are controlled by Huyton & Prescot signalbox, and Prescot closes at night. Blackpool line is Absolute Block from Kirkham North Jn you pick up semaphores at Poulton. I've not made my mind up about LED Dorman signals, I only work past 2 of them and they seem ok, I still prefer the old 'hotstrip' triangle in the lens of a traditional bulb signal though to confirm which signal the line applies to. Ground Position Lights were converted to LED operation a few years ago they now show Red/Red for danger instead of Red/White (although Ive seen a LED Red/White in Waverley station) Ive not seen a bulb GPL signal for some time now.

 

[di3nohab]

Been reading through this discussion:

LED signals are being fitted across the network as standard on major resignalling schemes which quite often involve axle counters but not exclusively.

They are also fitted as required and recommended by signal sighting committee's - either as part of a signalling enhancement project or following some sort of SPAD history.

The 'Four aspect' type with the two lenses are only able to display a yellow in the top light.

The top light is arranged so that when a double yellow is displayed the spacing between the top and bottom yellow is the same as the traditional filament type signal head.

The Crewe Coal Yard to Weaver Junction scheme was mentioned in one post and it was implied that all signals are being converted to LED and axle counters are being fitted. I can confirm that neither is true! LED signal heads have been fitted on two signals on the Down Fast & Down Slow at Winsford South Jn as part of the S&C renewal work last September. A further four LED heads were fitted on signals along the stretch between Hartford Junction and Acton Bridge with two fitted on each of the Down Slow (was Down Main) and the new Down Fast Line. Again this work was completed last year. This year, one existing LED signal at Weaver Jn is to be renewed and a new LED signal wil replace an existing filament type on the line that will become the Down Liverpool.

As far as I know virtually all Position Light/Shunt signals have now been replaced with the LED type - the main feature of these being that when at danger two Red lights are displayed unlike the traditional type which had a white 'pivot' light and only a single red light when at danger.

Hope this is useful/interesting!

 

[16CSVT2700]

Here's the Ansaldo design:

http://www.paulbigland.fotopic.net/p48189724.html

And the Dorman design:

http://www.paulbigland.fotopic.net/p48388116.html

The Dorman design is far better for railway applications as the lenses are larger and therefore easier to see. Those are the ones I've seen the most of, never seen the Ansaldo design.

 

[metrocammel]

Colchester is still a hotbed of the 'old fashioned' single lens type, I believe these date back to the late 50s- and are pretty much identical to the one in Paul's shot at Clacton (which I assume were fitted at pretty much the same time). I don't know if Clacton's have been replaced yet?

 

[1D53]

Leeds has traditional signal lens signals on all the gantries.

 

[ungreat]

IIRC colour blindness prevents one becoming a driver. Happy to be corrected though.

Correct..there are no exceptions with eyesight rules.
--- old post above --- --- new post below ---
There are some on the southern approaches to Peterborough as well..two aspect LED signals.

Also the signals between tunnels at KX are also of the LED type