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VMS lightweight Signals - cheap and "cheerful"

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The RETB on the East Suffolk line was taken out of use over the weekend of the 20/21 and Monday 22 October 2012. Convetional signalling was returned to the line using VMS lightweight signals.

 

I was down at Saxmundham on 31 October 2012 - for the RHTT - and snapped some photos of the new signals.

 

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Nice detail pics, not particularly popular with drivers I've talked to as they can temporarily spoil night vision when sitting at the signal they are so bright. Certainly bright in daylight.

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Nice detail pics, not particularly popular with drivers I've talked to as they can temporarily spoil night vision when sitting at the signal they are so bright. Certainly bright in daylight.

Is NR considering some form of ambient light attenuation, so as light levels fall, the brightness dims, too? Drivers' vision is important!

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Guest stuartp

Looks like it should blow away in anything stronger than a stiff breeze ! I like the modern take on 'pigs ears' on the side, but what happens when all those little holes get bunged up with snow ?

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I like the modern take on 'pigs ears' on the side, but what happens when all those little holes get bunged up with snow ?

 

Notice the pigs have 3 separate ears.

 

I'll let you know on the snow front.

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Nice detail pics, not particularly popular with drivers I've talked to as they can temporarily spoil night vision when sitting at the signal they are so bright. Certainly bright in daylight.

We had similar problems with early fibre optic banners. They were so bright at night that it was difficult to tell what they were showing until you got about 50 metres from them.

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Is NR considering some form of ambient light attenuation, so as light levels fall, the brightness dims, too? Drivers' vision is important!

Problem is a pigeon would probably sit on it and leave an obstruction on the light sensor making it bright anyway! ;)

I know there have been a lot of complaints but no idea if it will influence the new standards, that's up to the TOCs and FOCs to put pressure on the RSSB.

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Does anyone else think "1953 War of the Worlds" on first impression ??

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Problem is a pigeon would probably sit on it and leave an obstruction on the light sensor making it bright anyway! ;)

I know there have been a lot of complaints but no idea if it will influence the new standards, that's up to the TOCs and FOCs to put pressure on the RSSB.

This perfectly illustrates the whole problem with RSSB - they are one stage removed from the practical railway and thus anything which does pass to them takes forever (if ever) to get a result - Rule Book amendment requests from frontline operational folk already being a case in point.

 

The head on this signal looks like a bundlle of trouble just waiting to bounce on unsuspecting Drivers - tiny recessed lenses which as Stuart has already said will be an ideal target for snow - and it won't just be snow but all sorts of dust and muck getting unto those recesses and not only being difficult to get out but also possibly having an impact on the 'purity' of the colour the signal shows. In fact I wonder exactly how the heads/aspects will be cleaned when the need arises - perghaps a bucket of detergent and a long handled mop?

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They are spreading, the original ones appeared at Pelaw and have just been commissioned from Harrogate to Horsforth on the resignalling aboloshing Rigton and Horsforth boxes.

 

Mark Saunders

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In fact I wonder exactly how the heads/aspects will be cleaned when the need arises - perghaps a bucket of detergent and a long handled mop?

Then the damp gets in the supposedly sealed head and the thin tracks corrode and the whole head has to be replaced! No changing a single lamp on these things. LED roadsigns are just as bad, you see the LED's fail a few at a time making ever more confusing symbols, not quite the maintenance free solution they were trumpeted as.

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I prefer dormans - at least they look more like a signal and have a hood to keep off the snow. We shall see in time if these endure...

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16 November

 

On and off shot

 

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Emphasising the pigs ear

 

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Another weird one has appeared to replace UM35 at Reading I noticed this afternoon. Looks like a mixture of a couple of styles with the head being like the (non-working) experimental signal between Newport & Cardiff but the base being like the above signals/ Alas very difficulty located to get a pic.

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I have noticed a lot of normal 2,3 and 4 aspect heads are having the filament bulbs replaced with LEDs, that is quite good as the light is still focused normally.

One way of telling is that the green is more green rather than bluey green of the filament bulb, oh and you dont get the (slight) delay as the filament warms up and cools down. It changes aspect instantly.

 

I wont mention the technical failure of these LED bulbs when they are meant to show a flashing aspect, on the filament bulbs the time it takes for the filament to extinguish means that, as the power is re-applied, they appear to dim and then brighten. The LED ones go completely black before lighting back up, so technically a failure because the signal is not showing an aspect, only for a split second, but its still black!

When I mentioned this I was told to be quiet!

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so technically a failure

Really? Is there anything in the standard that requires a flashing aspect not to go completely out?

Keith

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A flashing aspect should NOT go completely out, a signal should display an aspect at all times.

 

A signal displaying no aspect at all (the time is not mentioned) is failed.

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Really? Is there anything in the standard that requires a flashing aspect not to go completely out?

Keith

 

Its actually more about preserving the life of the fillament more than anything else. Even in your home a fillament lamp is much more likely to blow on intial switch on due to the inrush of current than when it is actually working.

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I have noticed a lot of normal 2,3 and 4 aspect heads are having the filament bulbs replaced with LEDs, that is quite good as the light is still focused normally.

One way of telling is that the green is more green rather than bluey green of the filament bulb, oh and you dont get the (slight) delay as the filament warms up and cools down. It changes aspect instantly.

 

I wont mention the technical failure of these LED bulbs when they are meant to show a flashing aspect, on the filament bulbs the time it takes for the filament to extinguish means that, as the power is re-applied, they appear to dim and then brighten. The LED ones go completely black before lighting back up, so technically a failure because the signal is not showing an aspect, only for a split second, but its still black!

When I mentioned this I was told to be quiet!

 

That shouldn't be a problem because railway signals fitted with lamp proving have a special delayed action realy in the lamp proving circuit designed to get round this issues. If you are getting a blank signal indication it points to an issue with this relay or asociated circuitry.

 

The rate of flashing has not changed with LEDs and is designed to ensure drivers can recognise it at a varity of speeds. Besides the actual rules state that a driver traveling at linespeed must be able to see a signal for 10 seconds before they get to it and that for the last 5, nothing is permitted to obscure the view.

Edited by phil-b259

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A flashing aspect should NOT go completely out, a signal should display an aspect at all times.

A signal displaying no aspect at all (the time is not mentioned) is failed.

 

Below is the requirement for flashing signals from the current Railway Group Standard, it allows the light to be invisible for up to 50% of the time, Such an aspect can only be considered to not display an aspect when the flashing rate changes to the point where that time is exceeded.

Regards

Keith

 

2.2.1.4 Colour light signal lights that are designed to flash shall comply with the following

criteria:

a) Flash at a frequency of 60 (+/-10) cycles per minute.

B) Have a mark:space ratio that provides visibility of the signal light for 50% -

66% of each flashing cycle when observed in accordance with the relevant

standard performance category (see Appendix C).

c) Flash in synchronism within the signal head when the flashing double yellow

aspect is displayed.

d) Flash in synchronism throughout the primary and co-acting signal heads

when flashing aspects are displayed by co-acting signals.

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Why was the RETB abolished on the East Suffolk? It was adopted during the 1980s to reduce the costs of re-signalling that stretch and enabled it to remain open.

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I have noticed a lot of normal 2,3 and 4 aspect heads are having the filament bulbs replaced with LEDs, that is quite good as the light is still focused normally.

One way of telling is that the green is more green rather than bluey green of the filament bulb, oh and you dont get the (slight) delay as the filament warms up and cools down. It changes aspect instantly.

 

Yes, the stretch of the MML between Hendon and Mill HIll beside the M1 was recently upgraded using LED inserts in the old heads (which appear in some cases to date back to the 1960s). They will either be Dorman or Westinghouse WestLED inserts. Cheaper than buying new full heads.

 

London Underground have been using Dorman LED inserts in their platform repeaters and trackside dwarf heads for quite a while now, but have yet to use them in their full size heads on above-ground stretches; only parts of the Overground are so equipped, and those are again Dorman heads.

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Why was the RETB abolished on the East Suffolk? It was adopted during the 1980s to reduce the costs of re-signalling that stretch and enabled it to remain open.

 

The licences for the radio frequencies have expired or are due to expire along with the issue of component obsolescence. The re-signalling took advantage of the developments in axle counter technology and fibre optic transmission systems along with the investment in the Network Rail telecoms infrastructure to make it a cost effective scheme.

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