Stations with two signal boxes

[Guy Rixon]

I understand, I think, the basics of signalling and block working, but I am unclear on how a station is worked if it has a separate signal box for each end, when the boxes are only a few hundred feet apart. Can anybody explain? I'd particularly like to know what has to be done to accept a train into the station, and where shunting moves can be made by one box without the cooperation of the other.

[kevinlms]

I understand, I think, the basics of signalling and block working, but I am unclear on how a station is worked if it has a separate signal box for each end, when the boxes are only a few hundred feet apart. Can anybody explain? I'd particularly like to know what has to be done to accept a train into the station, and where shunting moves can be made by one box without the cooperation of the other.

The reason for two signal boxes, is usually the points and associated rodding are beyond the physical & legal limits, of operating them from say a centrally located box. In the case of a level crossing, a signal box needed to be located next to the crossing, to ensure the road was safe to operate the gates.

On many lightly trafficed lines, there might be only one signalman operating both signal boxes, with a bicycle to get from one end to the other.

[great central]

I'm sure it's not unique but Nottingham Victoria had 4 signal boxes.

Stockport still has two station boxes and just outside Edgely No's 1 and 2 almost within spitting distance of each other

Edited May 7, 2018 by great central

[The Stationmaster]

The simplest answer to the original question is that the section of line between the two 'boxes is worked as a block section and the regulations allow for those to quite an extent while the rest of the situation can be covered by the Signalbox Special Instructions and any Local Instructions in the sectional append.  Thus various things which weren't normally permitted in a block section would be specially authorised such as working in the wrong direction or propelling or permissive working of passenger trains.  

 

As far as acceptances were concerned the critical feature was the distance of the outermost Home signal of the 'box in rear from the Home Signal of the 'box in advance - more than 440 yards (even better if the Clearing Point was also clear of the next 'box's Home Signal/. But no real problem if there wasn't that much room available as all that was needed was Line Clear from the 'box at the advance end of the station before accepting a train from the 'box in rear.   Shunting into forward section or placing vehicles in rear of the Home Signal was simply standard Regulations applied or specially authorised as necessary - that of course required do-operative action on the part of both 'boxes but that was no different from the situation where the 'boxes were, say. 5 miles apart althoukling fouling of the Clearing Point at the other 'box did make a differeence.

 

Usually pretty straightforward at most places and basically boiling down to what needed to be done at that station and assessing if it was safe to do it before authorising it.  Does that help?

[Guy Rixon]

Stationmaster: thanks, that helps a lot. I have a few questions of detail if I may.

 

Suppose that, approaching from the north, there is an outer home signal, then homes signal controlling movements over the north throat, the throat pointwork, around 550 feet of platforms with platform starters, then the pointwork of the south throat. I presume that a train stoped at the home signals of the north throat is in station limits of the north box, whereas one stopped at the outer home is still in the section in rear of the north box. Where is a train when it moves into the platform? Is it in the short section between north and south boxes, or is it in station limits of the south box?

 

Extending the above scenario, suppose that there are southbound main and southbound relief lines, with the two joining after the platforms, in the south throat. It looks to me that clearing point for the south box will be beyond the junction of these two lines. Is it possible for trains to move into the station at the same time on the main and relief, and what does the south box man do to make this safe? Clearly the road can't be set for both trains. Does it help to have a warning signal to let one of the trains into the station?

 

Still thinking of this north-to-south approach, I guess that south box has no distant signals for southbound trains. Is this correct?

 

Finally, I presume that some of the signals are slotted. I broadly understand what slotting does, but not exactly where it is applied.

 

Thanks in advance for any advice.

[jonny777]

These diagrams might help -

 

https://signalbox.org/diagrams.php?id=667

 

https://signalbox.org/diagrams.php?id=668

 

 

They are for Sleaford East and West which controlled level crossings and junctions either side of the station. As you can see, they had their own distants which in practice were hardly in any other position than 'on' because they were reference to the platform starters at the other end of the station. 

[Oldddudders]

In the dim and distant days when BR was organised by Region, there was a line, mainly used by cross-London freights, which crossed the Regional boundary, Southern to London Midland, by a triangle junction at Kew. On the Southern side the two junctions were called Old Kew and New Kew, but at Waterloo little was known of the third junction, which was imagined to be called Far Kew Junction. As per the OP, this needed two boxes, called, inevitably Far Kew One and Far Kew Two!

[The Stationmaster]

Stationmaster: thanks, that helps a lot. I have a few questions of detail if I may.

 

Suppose that, approaching from the north, there is an outer home signal, then homes signal controlling movements over the north throat, the throat pointwork, around 550 feet of platforms with platform starters, then the pointwork of the south throat. I presume that a train stoped at the home signals of the north throat is in station limits of the north box, whereas one stopped at the outer home is still in the section in rear of the north box. Where is a train when it moves into the platform? Is it in the short section between north and south boxes, or is it in station limits of the south box?

 

You are correct until you get to the train being between the two signalboxes in the station platform - there it is in the block section between the two 'boxes

 

Extending the above scenario, suppose that there are southbound main and southbound relief lines, with the two joining after the platforms, in the south throat. It looks to me that clearing point for the south box will be beyond the junction of these two lines. Is it possible for trains to move into the station at the same time on the main and relief, and what does the south box man do to make this safe? Clearly the road can't be set for both trains. Does it help to have a warning signal to let one of the trains into the station?

 

Here various Regional differences start to set in - sorry.  Usually and in probably the vast majority of such situations a Warning acceptance would be used as there is , as you rightly say, no normal 440 yard Clearing Point.  But in some instance one of the lines might be trapped towards a short stub siding and depending on Regional differences a different form of acceptance might be permitted.  See the extreme example below.

 

Still thinking of this north-to-south approach, I guess that south box has no distant signals for southbound trains. Is this correct?

 

Not necessarily - again it depends on Regional/Company practice but in any event the South ;box would probably have soem sort of control over the North 'box's distant signal

 

Finally, I presume that some of the signals are slotted. I broadly understand what slotting does, but not exactly where it is applied.

 

Basically no real need for slotting but it did occur in some places - particularly if working in the wrong direction was authorised.  Slotting was more likely where the distance between the 'boxes and their signal was very short

 

Thanks in advance for any advice.

 

Now a really extreme example - the Up Main Platform Line at Reading where the East and West Main signalboxes were 770 yards apart but their signals were actually at the opposite ends of the platform (not unusual on the GWR/WR). the East 'box could accept trains over that line in five different ways, viz -

 

(Full) Line Clear,

Line Clear to Clearing Poiint Only (a special GWR/WR Regulation)

Warning Acceptance,

Permissive Acceptance (if the platform was already occupied by another train)

Shunting Into Forward Section acceptance

[Nearholmer]

I can't resist mention of Tunbridge Wells West, where B Box was a brilliant little working museum, until closed by ..............

 

I have a dim recollection that it could operate with the A Box switched-out, which would certainly have covered the needs of traffic during the very long somnolent periods there.

 

Did I dream that, or is such an arrangement allowable/feasible?

[Wheatley]

You are correct until you get to the train being between the two signalboxes in the station platform - there it is in the block section between the two 'boxes

Mike alludes to an important point here, often lost on a lot of modellers; not all stations are within Station Limits, and not all Station Limits have a station in them.

[The Stationmaster]

Mike alludes to an important point here, often lost on a lot of modellers; not all stations are within Station Limits, and not all Station Limits have a station in them.

 

A good point.  The term 'Station Limits' has nothing whatsoever to do with the presence or otherwise of a station and is actually a technical operational term used to distinguish a particular section of railway from the section of railway covered by the term 'Block Section.  Station Limits lies between the outermost (or rear most) Home Signal at a signalbox and that signalbox's most advanced starting signal (nowadays often referred to as the Section Signal because it controls entry to the Block Section in advance).

 

Certain operational activities and movements can be carried out in Station Limits which are not permitted (in normal working) in a Block Section such as propelling, working in the wrong direction, or moving vehicles without a brakevan).  The OP seems to have understood the differeence so apologies to him for using his thread to drop in a basic explanation.

[sir douglas]

stations often had 2 boxes as there is a lot going on at either end needing to be controlled but there isnt the space or visibility for one large box in the middle

 

Wakefield Kirkgate had the Westagte line, 4 tracks from Horbury, wagon lift sidings and a warehouse siding on the west side and on the east side was the triangle junction, carraige sidings, goods shed and withams sidings

 

Lancaster Green Ayre had 2 boxes, West side had loco shed, goods yard and castle branch, East side had coal yard, the throat of a marshalling yard and wagon works

[Joseph_Pestell]

I can't resist mention of Tunbridge Wells West, where B Box was a brilliant little working museum, until closed by ..............

 

I have a dim recollection that it could operate with the A Box switched-out, which would certainly have covered the needs of traffic during the very long somnolent periods there.

 

Did I dream that, or is such an arrangement allowable/feasible?

 

It would only be practicable if the signalling was such as to allow trains running westwards to run into the platform by the station building - so no point operation required at the A box.

 

The signalling seems to indicate that this was not the case.

[Nearholmer]

No point operation was needed at the other end of the station for normal operation, because it was double track beyond what we see here, and the various bays and loops weren't needed. But, I still don't know if I dreamt this 'switching out'. OD will probably know for sure.

[Joseph_Pestell]

No point operation was needed at the other end of the station for normal operation, because it was double track beyond what we see here, and the various bays and loops weren't needed. But, I still don't know if I dreamt this 'switching out'. OD will probably know for sure.

 

We should probably be able to find out if there was a switch from SRS records.

[Oldddudders]

I can't resist mention of Tunbridge Wells West, where B Box was a brilliant little working museum, until closed by ..............

 

 

Guilty as charged!

[73c]

My favorite, are the 2 at West Croydon. Closest I've seen 2 boxes. 

[Nearholmer]

Showy extrovert one, and the shy, retiring one?

[73c]

That's them. Got a visit to the one under the ramp and Gloucester Rd many years ago.