Flashing yellows question

[martin2345uk]

Say a junction has flashing yellows... the junction signal has 3 junction indicators, all 3 diverging routes are the same speed... can you get flashing yellows to any one of them? Or would the flashers be for one route and for the other 2 you'd get, say, approach release from red, even though they're all the same speed?

 

[DeparturesBeck]

Both situations you describe can have flashing yellow sequences, they do not have to apply to all routes even where diverging speeds are the same, but can be.

 

[Railsigns]

It would depend on the circumstances. If all three routes had similar characteristics (e.g. all three electrified) and the permissible speed of divergence at the junction was similar (all within 10 mph of each other), then it could be permitted.

I know of flashing yellow sequences that apply to two different diverging routes beyond the same junction signal; three routes would be unlikely, though.

 

[louis97]

I know of flashing yellow sequences that apply to two different diverging routes beyond the same junction signal; three routes would be unlikely, though.

Signal DW5316 at LNW Junction approaching Derby from Birmingham has a flashing yellow sequences for the 3 diverging routes to the Down Tamworth Fast, Up Tamworth Slow and Down Tamworth Slow. It has a preliminary route indicator on approach.

 

[Railsigns]

Signal DW5316 at LNW Junction approaching Derby from Birmingham has a flashing yellow sequences for the 3 diverging routes to the Down Tamworth Fast, Up Tamworth Slow and Down Tamworth Slow. It has a preliminary route indicator on approach.

That's interesting, thanks.

Come to think of it, the flashing yellow sequences approaching Birmingham International from the south and north apply to four and three different diverging routes, respectively. The PRIs certainly help in this situation.

 

[martin2345uk]

Signal DW5316 at LNW Junction approaching Derby from Birmingham has a flashing yellow sequences for the 3 diverging routes to the Down Tamworth Fast, Up Tamworth Slow and Down Tamworth Slow. It has a preliminary route indicator on approach.

That’s the exact kind of situation that prompted the question - a signal on approach to Slough West Junction on the Up Relief can put you onto the Down Relief, Up Main, and Down Main, all at 40mph. I’ve not be able to find out which route(s) the flashing yellow sequence would be used for, there are no Preliminary Route Indicators on approach!

 

[Geezertronic]

Signal between Marston Green and Birmingham International looks to have flashing yellows when a train is directed into Platform 5 (not sure about Platforms 1, 2 & 3). I've seen it when waiting at Marston Green, wondered, and a quick check shows the passing service into Platform 5 at International (which is an Avanti 390 service in my case)

 

[The Planner]

Signal between Marston Green and Birmingham International looks to have flashing yellows when a train is directed into Platform 5 (not sure about Platforms 1, 2 & 3). I've seen it when waiting at Marston Green, wondered, and a quick check shows the passing service into Platform 5 at International (which is an Avanti 390 service in my case)

No flashers into 3 I think.

 

[Joliver]

That’s the exact kind of situation that prompted the question - a signal on approach to Slough West Junction on the Up Relief can put you onto the Down Relief, Up Main, and Down Main, all at 40mph. I’ve not be able to find out which route(s) the flashing yellow sequence would be used for, there are no Preliminary Route Indicators on approach!

Surely it would flash for all diverging routes set? You have the signal protecting the junction with JI 4, 5 and 6 showing where you're being routed.

 

[martin2345uk]

I have just been reliably informed that it only flashes when routed onto the Up Main!

 

[class ep-09]

Approaching Reading on Dn Main - double flasher may take you in to plat 7 or 8.

 

[Tim M]

Quick reminder, these signals don’t actually ‘flash’ they ‘occult’, i.e. they go dark. If the flashing device fails the signal must revert to a safer steady aspect.

 

[Efini92]

That’s the exact kind of situation that prompted the question - a signal on approach to Slough West Junction on the Up Relief can put you onto the Down Relief, Up Main, and Down Main, all at 40mph. I’ve not be able to find out which route(s) the flashing yellow sequence would be used for, there are no Preliminary Route Indicators on approach!

I think it depends on the standards when the signalling was installed.
Approaching euxton junction on the up slow flashing yellows could route you onto the up fast or the up Bolton.

 

[Annetts key]

Quick reminder, these signals don’t actually ‘flash’ they ‘occult’, i.e. they go dark. If the flashing device fails the signal must revert to a safer steady aspect.

The conventional lit (filament lamps) flashing aspects do not actually go out completely. Instead the lamp current is reduced to a level where the system can still detect that the filament is intact, but at a level low enough such that the aspect looks dark to a driver.

If at any time the lamp current drops to zero, the previous signal will go to red.

If at any time the system detects a flasher fault, the flashing aspect sequence will be cancelled. The junction signal will revert to red and become approached released. And the signals in rear will revert to the appropriate aspects as per a normal aspect sequence.