Flashing aspect rates

[Prince1041]

Aoplogies for the newbie question,

would anybody be able to advise on the on and off times (in mSeconds) for flashing aspects protecting junctions?

I have a Westinghouse 4 aspect signal head for a garden ornament and wish the sequence to be as true as possible.

many thanks.

 

[Boilinthebag]

Not sure of what help it will be, but the flashing aspects approaching Moreton are visible in this BR signalling video BR Signalling which is probably more of the age of your signal head.

 

[The Puddock]

Aoplogies for the newbie question,

would anybody be able to advise on the on and off times (in mSeconds) for flashing aspects protecting junctions?

I have a Westinghouse 4 aspect signal head for a garden ornament and wish the sequence to be as true as possible.

many thanks.

Bright = 670ms ± 70ms

Dim = 330ms ± 30ms

 

[Tim M]

I think (it’s been a long time ……….) that Flashing Aspects are strictly occulting indications. That means they switch to dark (hence occulting) so that if the flasher function fails the aspect reverts to a more restrictive steady yellow or double yellow as required. Others might be able to confirm.

 

[John Webb]

Aoplogies for the newbie question,

would anybody be able to advise on the on and off times (in mSeconds) for flashing aspects protecting junctions?

I have a Westinghouse 4 aspect signal head for a garden ornament and wish the sequence to be as true as possible.

many thanks.

At the preserved St Albans South signal box, we have several of these signal heads:

Here showing the sequence behind a train about to 'turn off' to the left.

We've not used the original 12volt 24Watt filament bulbs, but have replaced them with 3.5 W LED reflector bulbs (MR16/GU5.3 types) to give a broader spread of light to make viewing easier for our visitors. We have a sequencer located in the LOC (Location Cabinet) partly hidden by the Banner Repeater - seen here:

 

[43066]

At the preserved St Albans South signal box, we have several of these signal heads:
View attachment 148786
Here showing the sequence behind a train about to 'turn off' to the left.

We've not used the original 12volt 24Watt filament bulbs, but have replaced them with 3.5 W LED reflector bulbs (MR16/GU5.3 types) to give a broader spread of light to make viewing easier for our visitors. We have a sequencer located in the LOC (Location Cabinet) partly hidden by the Banner Repeater - seen here:
View attachment 148787

Sorry to be pedantic, but the first photo doesn’t show the correct sequence for flashing yellows. On four aspect it’s YY (flashing) Y (flashing), Y (steady, plus feather), then the theoretical red.

You appear to be showing there what’s commonly known as approach/release - ie the train is checked down to crawl towards a red, which steps up to a proceed aspect, plus feather.

 

[InkyScrolls]

Sorry to be pedantic, but the first photo doesn’t show the correct sequence for flashing yellows. On four aspect it’s YY (flashing) Y (flashing), Y (steady, plus feather), then the theoretical red.

You appear to be showing there what’s commonly known as approach/release - ie the train is checked down to crawl towards a red, which steps up to a proceed aspect, plus feather.

You beat me to it!

 

[Railsigns]

Sorry to be pedantic, but the first photo doesn’t show the correct sequence for flashing yellows. On four aspect it’s YY (flashing) Y (flashing), Y (steady, plus feather), then the theoretical red.

You appear to be showing there what’s commonly known as approach/release - ie the train is checked down to crawl towards a red, which steps up to a proceed aspect, plus feather.

All it's showing is a normal aspect sequence up to a red signal, while another train is somewhere between that signal and the junction signal.

 

[John Webb]

Sorry to be pedantic, but the first photo doesn’t show the correct sequence for flashing yellows. On four aspect it’s YY (flashing) Y (flashing), Y (steady, plus feather), then the theoretical red.

You appear to be showing there what’s commonly known as approach/release - ie the train is checked down to crawl towards a red, which steps up to a proceed aspect, plus feather.

You beat me to it!

All it's showing is a normal aspect sequence up to a red signal, while another train is somewhere between that signal and the junction signal.

Gentlemen, you are all correct in your comments. We don't have a 'flashing yellow' sequence on these heads. I was just trying to illustrate to the OP how we'd avoided using the original signal lamps; we found their beam was too narrow and too bright for comfortable viewing by our visitors. Also, being a relatively early installation on our site, we'd shied away from using 100 volts. (We also now have some LED heads and have used both the standard 100v AC supply and include a flashing yellow sequence.)
My apologies if my original post above didn't make my intent in posting it completely clear.

 

[Chrius56000]

Hi!

. . .The line diagram of Flashing Yellow Signalling in "British Railway Signalling" by Alan Williams amd Geoffrey Kitchenside quoted "70 cpm" or 1.1 Hz, which is 900 ms, so Member Puddock's estimate is about right – incidentally O.S. Nock's green I.R.S.E. Signalling Textbook doesn't quote the exact flashing speed, but I think it does mention that with filament bulb signals it was standard practice not to totally switch off the signal lamp filaments for the flashing sequence in order to help prolong lamp life!

Chris Williams

 

[Pigeon]

I'd be amazed if it wasn't, that trick is standard for nearly all "industrial" incandescent lamp flashing applications, especially where the lamps are inaccessible and/or the highest possible reliability is desired.

 

[Annetts key]

Flashing aspect filament lamps are indeed maintained "warm" rather than switched off completely.

 

[Crossover]

Hi!

. . .The line diagram of Flashing Yellow Signalling in "British Railway Signalling" by Alan Williams amd Geoffrey Kitchenside quoted "70 cpm" or 1.1 Hz, which is 900 ms, so Member Puddock's estimate is about right – incidentally O.S. Nock's green I.R.S.E. Signalling Textbook doesn't quote the exact flashing speed, but I think it does mention that with filament bulb signals it was standard practice not to totally switch off the signal lamp filaments for the flashing sequence in order to help prolong lamp life!

Chris Williams

I'd be amazed if it wasn't, that trick is standard for nearly all "industrial" incandescent lamp flashing applications, especially where the lamps are inaccessible and/or the highest possible reliability is desired.

Not railway but doing stage work, with filament lamps doing something like a chase, we’d keep them warm in an ‘off’ state. Likewise if you needed a lamp to snap on (like turning on a room lamp), in the previous scene you’d keep the necessary lamps warm to reduce the likelihood of blowing the lamp on the snap. Usually the ‘pre warm’ would be around 10% power which wasn’t bright enough to be seen (most stage lamps would be 500-1000W)

Obviously, with LED, less thought is required on this front

 

[The Puddock]

Hi!

. . .The line diagram of Flashing Yellow Signalling in "British Railway Signalling" by Alan Williams amd Geoffrey Kitchenside quoted "70 cpm" or 1.1 Hz, which is 900 ms, so Member Puddock's estimate is about right

It wasn't an estimate, it was quoted directly from the standards.

 

[Ediswan]

Usually the ‘pre warm’ would be around 10% power which wasn’t bright enough to be seen (most stage lamps would be 500-1000W)

It helps that an incandescent lamp running at 10% power will produce significantly less than 10% of its nominal visible light.