Fringe signalboxes - how do they work?

[Ken H]

I am talking about a manual box where the next box is a powerbox.
For example, Hellifield. To the east its York ROC, to the west its manual box Settle Jct.
What special tasks does the signal man have do to send and accept trains from the ROC?
Does this differ between different fringe locations?
Are there any power boxes that have block instruments and bells to communicate with a fringe box.
Can a fringe box be switched out, so the powerbox has to communicate with anothe box? So in the Hellifield example, can Hellifield be switched out and trains offered and accepted between York ROC and Settle Jct?

 

[edwin_m]

In my experience with the early IECCs, each fringe box had a terminal with a simplified version of a track diagram, where the signaller could enter the descriptions of trains heading for the IECC area and see those of trains approaching from it. Track Circuit Block applied between the fringe box and the IECC, which means that trains were not offered and accepted but would just appear on each other's displays (unless specific arrangements were made to stop them). A single track fringe would need some kind of offer and accept process which I think was done by electronic "buttons" on the two screens.

None of the ones I was involved with could be switched out. I believe some panel boxes have block bells for emergency use.

 

[lineclear]

Absolute block regulations require that a train must pass the clearing point complete with tail lamp before 'train out of section' can be sent to the box in rear. Difficulty in observing this means that absolute block generally isn't used where the signal box not at the relevant end of the block section.

As mentioned above, trains are described, not accepted, between boxes where TCB regulations apply (except when TCB regulation 3.5 is applied).

The only boxes that can switch out work absolute block both ways. The switch connects the block instruments and bells of the adjacent boxes to each other, bypassing the closed box. As 'fringe' boxes nearly always work TCB to larger boxes, no fringe box can switch out as far as I know.

 

[Ken H]

Thanks for the clear answers.

 

[High Dyke]

Both edwin_m and lineclear have explained it well. There will always be some slight differences depending on location. A couple of now closed boxes I worked used Train Describers to forward descriptions. However one box then just cleared their Starting signal, but the other box was a single line chord that required either you or the PSB to provide a release. Nowadays I work a number of boxes where it goes to/from single line sections the release is given by either a request alarm or by forwarding a bell signal, and then either a switch or lever operated.

 

[matchmaker]

Until Newtonhill closed recently, it worked AB to Aberdeen panel on the Up line. Down line was TCB.

 

[edwin_m]

Until Newtonhill closed recently, it worked AB to Aberdeen panel on the Up line. Down line was TCB.

I believe it was south of Aberdeen, so the Newtonhill signaller would have been able to observe tail lamps of Up trains. The reverse wouldn't be true for Down trains at Aberdeen, hence the TCB. Any other examples of fringes where AB is used going away from the power box?

 

[Kneedown]

Are there any power boxes that have block instruments and bells to communicate with a fringe box.

Leicester power box certainly had a block instrument for communicating with Frisby SB.

 

[LowLevel]

I believe it was south of Aberdeen, so the Newtonhill signaller would have been able to observe tail lamps of Up trains. The reverse wouldn't be true for Down trains at Aberdeen, hence the TCB. Any other examples of fringes where AB is used going away from the power box?

Worksop PSB works absolute block to and from Elmton and Creswell Junction in theory - in practice it's actually to Shirebrook Junction as E&C has been semi permanently switched out bar maintenance or failures since 2010 or so.

 

[MadMac]

Any other examples of fringes where AB is used going away from the power box?

Motherwell had this arrangement for the fringes to Bellside Junction and Midcalder Junction. Edinburgh had it for the fringe to Bathgate Central. Kilmarnock had AB to Hurlford added about 10 years ago to enable Hurlford to be switched out permanently.

 

[MarkyT]

If you can see out of the window at a PSB and observe the passing tail light of a train leaving the section in question there's no reason why that line could not be signalled using absolute, token or tokenless block, even if the majority of the area controlled by the PSB is TCB. Sometimes, just as at a small number of mechanical boxes in later years, a CCTV camera could be placed at the clearance point for tail light observation. In the old signalling, there was one of these at Oxford for the tokenless block on the Bicester line, before the line was redoubled and resignalled under TCB recently. Even where full TCB working applies to fringe boxes or indeed other adjoining TCB panel boxes, block bells are usually retained in some form for emergency description should the fringe TD unit or its communications link fail. The original 60s WR PSBs had old fashioned wooden block bell instruments hidden inside the consoles for such purposes, although the send key would be replaced by a push button on the face of the panel.

 

[Tomnick]

Leicester power box certainly had a block instrument for communicating with Frisby SB.

It’s common in powerboxes of that era, but only a bell (intended for emergency bell signals or use during degraded working) rather than a block instrument. Frisby’s bell is long gone now, replaced by an emergency alarm, but Uffington still has one to each of Peterborough PSB and Helpston.

I recall reading that Swinderby’s bell to Doncaster was routinely used for describing trains for quite a long period when the train describer wasn’t playing!

Worksop PSB works absolute block to and from Elmton and Creswell Junction in theory - in practice it's actually to Shirebrook Junction as E&C has been semi permanently switched out bar maintenance or failures since 2010 or so.

For completeness, given the previous mention of observing tail lamps, a tail lamp camera is provided for Down trains in this case (curiously, Shirebrook also has one, as Up trains going onto the branch don’t pass the box).

Perhaps one of the most notable survivor is Dinting’s fringe to Manchester East (is it in the ROC yet?), still absolute block with a (modern) block bell on the desk and indications on the workstation IIRC, trains given complete by a “train arrived complete” plunger at the first station beyond the home signal.