Signal boxes at triangular junctions

[2192]

In the days of mechanical signalling, and before power operated points existed, was it possible for one signal box placed in the middle of the triangle to control the points at all three junctions? Or was the distance too great for the strength of the average signaller? If yes, do you know of any examples?

 

[D Williams]

Tolcarne Junction. The box wasn't in the middle though.

 

[IanH440]

Severn Tunnel Junction at Salop?

 

[Gloster]

The Cornwall Railway Society’s site says that the the east to south curve at Tolcarn Junction was out of use from the 1890s to 1931. Before that signalling and point control were probably fairly rudimentary.

At Bradford Junction there were three boxes until 1933.

 

[John Webb]

In the days of mechanical signalling, and before power operated points existed, was it possible for one signal box placed in the middle of the triangle to control the points at all three junctions? Or was the distance too great for the strength of the average signaller? If yes, do you know of any examples?

It wasn't a case of the distance limit being the strength of the signalman. The Board of Trade who controlled railways for many decades set limits over which points could be manually worked from a signal box. The limitation was mainly so that the signalman could see the points were correctly set and not alter them when a train was passing over them. The distance was increased as improved methods of monitoring points developed - it reached a maximum of 350 yards. Remote operation by electric point machines allowed longer distances, of course.
Therefore the majority of triangular junctions had at least two and often three boxes, at least in their early days.

 

[class68fan]

Greenford East

 

[Ken H]

Did Dinting ever have more than one SB?

 

[Gloster]

Greenford East

Greenford seems to have had three boxes as late as 1956, when South Loop and East Loop closed.

 

[ANDREW_D_WEBB]

Bradford Junction just north of Trowbridge had a signal box when it was a triangular junction.

 

[30907]

In the days of mechanical signalling, and before power operated points existed, was it possible for one signal box placed in the middle of the triangle to control the points at all three junctions? Or was the distance too great for the strength of the average signaller? If yes, do you know of any examples?

Arundel Jn, Minster and Bradford(-on-Avon) Jn come to mind.
From the SRS site, Arundel Jn had one motor-worked point at the Littlehampton end (its "pair" being self-acting); Minster looks to have had the same at the South junction - both were SR rationalisation.

The "new" Bradford Jn box (already mentioned) was cunningly sited halfway between the West North and South junctions, and I imagine the rodding to North West ran direct from the box, at right angles to the rest, so could well qualify.
EDIT: got disorientated - see Gloster's post later

Severn Tunnel Junction at Salop?

Severn Bridge Jn doesn't actually control all the triangle - and even the junction at Abbey Foregate looks to have been added to its layout as a "modern" rationalisation - I would hazard a guess that the points are motorised (Tim Dunn, are you on here?!).

As John Webb has said, the vast majority of triangles needed 3 boxes.

 

[edwin_m]

Another issue would be confirming trains complete by observing the tail lamps, which would be difficult if the trains in question didn't pass the box. Before the days of cameras it would presumably have required the guard to phone the signaller, which would obviously require the train to stop so wasn't really viable for frequent or fast services.

 

[Gloster]

Bradford Junction box was on the inside of the triangle about half-way between the North and South Junctions, which were (if I remember correctly) always worked manually, while the West Junction had motor points. (And a right pain it was having to wait for tail-light advice for Down trains, not that there were many of them.)

EDIT: As @edwin_m says, the train had to stop and the guard get on the ’phone to say ‘train arrived complete with tail lamp’, (or something like that).

 

[_toommm_]

Did/does Dinting control all three sides?

 

[P Binnersley]

Yes, the signal box was on the main (Manchester - Hadfield) line and the rodding for the Glossop end of the triangle ran out the rear of the box, under the road and across the middle of the triangle. I think last time I went past it looked like the point is now motor worked as the rodding had gone.

You can see the boards covering the old route in Google Street View (if you go back to the 2009 view you can see the rodding). The Satellite image shows a line which may be the rodding.

 

[Llanigraham]

Doesn't Sutton Bridge Box control the southern Marches Line junction at the Severn Bridge triangle?
I shall have to have a good look next time I'm passing.

 

[2192]

Thanks, everyone. OP

 

[Annetts key]

Bradford Junction box was on the inside of the triangle about half-way between the North and South Junctions, which were (if I remember correctly) always worked manually, while the West Junction had motor points. (And a right pain it was having to wait for tail-light advice for Down trains, not that there were many of them.)

EDIT: As @edwin_m says, the train had to stop and the guard get on the ’phone to say ‘train arrived complete with tail lamp’, (or something like that).

If I remember correctly, the motor points controlled from Bradford Junction SB were powered by the signaller operating a hand generator.

The distance that mechanical points could be from a signal box were also limited by the mechanical losses caused by having to have multiple compensators. Compensators are needed to deal with the expansion and contraction of the metal rodding runs.

Track circuits, electrical detection combined with electric lever locks did solve the problem of the points being out of view of the signaller. But until mains power was provided, did give the S&T more work to do, having to regularly change the cells (batteries).

 

[Gloster]

If I remember correctly, the motor points controlled from Bradford Junction SB were powered by the signaller operating a hand generator.

As far as I can remember, by the time I was there the West Junction points had a mains supply. How long it was like that I do not know: it might have been an ancillary bit of work to the Westbury resignalling, or even the Bristol one. I have a vague feeling that the hurdy-gurdy was still there, but they often seem to have been retained in case of power cuts.

 

[Annetts key]

Ooo, far too long ago for me to remember

 

[Tomnick]

Doesn't Sutton Bridge Box control the southern Marches Line junction at the Severn Bridge triangle?
I shall have to have a good look next time I'm passing.

No, Severn Bridge Junction does. The colour-light home signal before English Bridge Junction reads around the loop and all the way into the platforms at the station.

 

[40C]

Marsh Junction at Grimsby was like this.

 

[Llanigraham]

No, Severn Bridge Junction does. The colour-light home signal before English Bridge Junction reads around the loop and all the way into the platforms at the station.

Thanks. I couldn't remember as it's a few years since I've been up into the Box; normally done on Briefing days before I caught the train home.

 

[Midland Man]

In the days of mechanical signalling, and before power operated points existed, was it possible for one signal box placed in the middle of the triangle to control the points at all three junctions? Or was the distance too great for the strength of the average signaller? If yes, do you know of any examples?

Apologies for delayed reply. After consulting with colleagues St Dunstans signal box (controlling the lines from Bradford Exchange and Leeds to the Queensbury line) controlled a triangular junction - all mechanical (says the last signalman to work it). This replaced boxes at each corner of the triangle. Queensbury triangle had three boxes, but later only had one signal box, again all mechanical points, and easy to work according to another colleague (now deceased). The runs were shortened by not following the curves but going straight across at both of those locations and probably elsewhere.
regards David
Ex signalman, regional inspector etc.

 

[2192]

Apologies for delayed reply. After consulting with colleagues St Dunstans signal box (controlling the lines from Bradford Exchange and Leeds to the Queensbury line) controlled a triangular junction - all mechanical (says the last signalman to work it). This replaced boxes at each corner of the triangle. Queensbury triangle had three boxes, but later only had one signal box, again all mechanical points, and easy to work according to another colleague (now deceased). The runs were shortened by not following the curves but going straight across at both of those locations and probably elsewhere.
regards David
Ex signalman, regional inspector etc.

Thanks. 2192

 

[Ken H]

Apologies for delayed reply. After consulting with colleagues St Dunstans signal box (controlling the lines from Bradford Exchange and Leeds to the Queensbury line) controlled a triangular junction - all mechanical (says the last signalman to work it). This replaced boxes at each corner of the triangle. Queensbury triangle had three boxes, but later only had one signal box, again all mechanical points, and easy to work according to another colleague (now deceased). The runs were shortened by not following the curves but going straight across at both of those locations and probably elsewhere.
regards David
Ex signalman, regional inspector etc.

Always looks odd to me seeing point rodding nowhere near a track.