(Another) MPD

[Golden Eagle]

As someone "returning to model railways" for the first time in 25y, I would be grateful for the thoughts of those with far greater experience and knowledge regarding this possible plan for a MPD.

 

 

 

Setting is roughly north-east Scotland, at the peak of the the LNER (ie I've got to justify stabling a trio of A4s!) accepting that I'm using a ramp for coaling (similar to St Margaret's in Edinburgh, I think) rather than a "cenotaph" (because I prefer the look...if I've picked up the terminology correctly from a month of lurking, "Rule 1 applies"?). As well as the movements of locomotives around the MPD for ash dropping, coaling, turning, watering, sanding and time "On The Shed", I hope to use a yard pilot 0-6-0 to move coal wagons between coal stage and adjacent siding. ("Steady state" being six wagons at the top of the ramp, six in the siding) with the potential to for an O4 to deliver rakes of "full" wagons and remove the empties.

 

Main constraint is that the baseboards cannot be deeper than 64cm for the first 70cm at the left-hand end (ie to roughly the mid-point of the Coaling Stage), thus I have a whole 2cm of additional depth to play with. I therefore took the gist of the "linear" MPD at Norwood Junction (courtesy of a suggestion in another MPD-related thread), rotated it through 90 degrees, "mirroring" it to avoid everything being hidden behind the coaling ramp and stage...and transplanted it to Scotland. If necessary, there is space available to the right, where I anticipate that the MPD will feed into a "main line" layout in due course.

 

Specific questions (in addition to any general observations which will be most welcome):

1) How were points actually operated in a MPD? Some layouts seem to include a signal box (though this may be more to do with adjacent main line operations), or would crews operate manual point levers at each turnout? Would there be any signalling other than a "Stop" ("Home"?) signal at the exit to the MPD? Anything around the various tracks? 

2) I have put trap points at the bottom of the coal ramp and on the exit road. Should there be any others?

3) Have I missed anything which ought to be present?

4) Are there any obvious showstoppers?

 

Many thanks for your thoughts!

 

Iain

Edited December 29, 2020 by Golden Eagle

[Flying Pig]

The general layout looks quite similar to Aberdeen Ferryhill.  Alternatively, Dundee might be worth looking at.  Arranging it with the headshunt (east end) at the narrow and of the layout and the entrance/exit roads disappearing behind the shed at the right might hide less of the action than your current plan. 

[The Stationmaster]

3 hours ago, Golden Eagle said:

 

 

Specific questions (in addition to any general observations which will be most welcome):

1) How were points actually operated in a MPD? Some layouts seem to include a signal box (though this may be more to do with adjacent main line operations), or would crews operate manual point levers at each turnout? Would there be any signalling other than a "Stop" ("Home"?) signal at the exit to the MPD? Anything around the various tracks? 

2) I have put trap points at the bottom of the coal ramp and on the exit road. Should there be any others?

3) Have I missed anything which ought to be present?

4) Are there any obvious showstoppers?

 

Many thanks for your thoughts!

 

Iain

1.  points were worked by hand levers which were right next to them

You might have an exit signal worked by a nearby signal box although the exit might well be through a yard under the control of Shunters - that really depends how close it is to a running line

2. Coal stage trap is correct - and for safety's sake might be worked by a ground frame rather than a hand lever in some places. Even a 'hold down' lever could be used but they had their risks if somebody was distreacted while they were meant to be holding down the lever.

An exit trap point needs to be at the shed exit so right at the end of the layout - if there is one at all.  It all depends what that line connects to

3. No - although you ash pits on some railways would be much nearer to, or right in front of, the coal stage.  Maybe not enough coal siding space but no problem if there is a yard nearby.

4.  Some potential headaches -

a. Even with the dotted line connection you will have an unavoidable choke point between engines coming on shed from the turntabble and those moving around between shed roads/going off shed.   If nothing eldse it will give you plenty of operating fun keeping that lot flowing.

b. The breakdown train siding is not well situated. far better to have it alongside the shed where it would also act as a stores road (and you need buildings for stores and offices etc along the side of the shed

 

I think the sand house is in the wrong place as it would be used when engines are being prepared - not when they are coming on shed and being disposed.

 

[Golden Eagle]

4 hours ago, Flying Pig said:

The general layout looks quite similar to Aberdeen Ferryhill.  Alternatively, Dundee might be worth looking at.  Arranging it with the headshunt (east end) at the narrow and of the layout and the entrance/exit roads disappearing behind the shed at the right might hide less of the action than your current plan. 

So...somehow I managed to miss the inclined coal ramp when looking at the Ferryhill map, so I'm not entirely "out of area" after all! Might have to wrap the coaling stage in granite, but I'll worry about that down the line!

 

In this draft, I've moved the shed to the west, and, in so-doing hopefully addressed The Stationmaster's point about the choke point between turntable and shed roads. That also put the shed to an area where I could add a stores road to the north and an additional building attached to the south wall of the shed, with the option of further buildings to the east.

 

Sand house and water crane positioned to allow them to support locomotives coming off the turn-table or out of the shed (presumably more useful than having them in the head shunt, though with a little reworking, I could probably get them in between the head shunt and the road as it comes off the turntable).

 

With reference to The Stationmaster's other points: 

Ash pits moved closer to the coaling stage (I thought I read in a previous discussion that ash pits immediately in front of the coaling stage were not advised as they would rapidly fill with coal which missed the tender?). Breakdown crane hopefully now more sensibly located and the exit trap moved beyond the entry crossover. In terms of "where" the exit road goes...probably to either a terminus or (more likely) a through station, most likely having gone through a tunnel and round a corner to get there. I haven't quite got that far with the detailed planning!

 

 

With the locomotives going nose-first into the shed, and backing out, would the external inspection pits still sit to the west, or would they be more usefully placed on the final approach?

 

Thank you both for your input. Much appreciated.

[Mike 84C]

Deffo' put the inspection pits on the east end of the shed and they do not need to be deep. Think rails at chest level on Mr Average and limboing under the engine. Ash pits right to the coal stage, one long pit, the man filling the tubs would not put much coal in the pit. It was b----- hard work and they were not daft men.  If you have the room I would bring the three tt roads into one before the tt  giving  one engine length before going onto the tt. I like the idea of 6 wagons on the coal stage  4/5 being visible 1/2 inside being emptied and 1/2 empty on the "downward" side.

[Golden Eagle]

31 minutes ago, Mike 84C said:

Deffo' put the inspection pits on the east end of the shed and they do not need to be deep. Think rails at chest level on Mr Average and limboing under the engine. Ash pits right to the coal stage, one long pit, the man filling the tubs would not put much coal in the pit. It was b----- hard work and they were not daft men.  If you have the room I would bring the three tt roads into one before the tt  giving  one engine length before going onto the tt. I like the idea of 6 wagons on the coal stage  4/5 being visible 1/2 inside being emptied and 1/2 empty on the "downward" side.

Hi Mike - yes - that's exactly the idea for the coal ramp. I saw some suggestions about using a servo to move a pin up and down as an "axle brake" which would allow me to roll the wagons back down the slope one axle at a time. I might even "unload" the coal from the "empty" wagons using a magnet on the end of a "fishing rod" (suspending disbelief for the necessary manoeuvre!)

 

Converging the TT roads into a single length adds about 60cm to the length of the plan, which is not impossible, but eats up a lot of the available "free" space to the right. That's something I could do in the future once I've worked out how much of that I need for whatever I do with the rest of the layout!

 

East-sited inspection pits and long ashpits to the coal stage it is! 

[TheSignalEngineer]

A few points from me.

1) Why is the shed open at both ends? I can see no reason for this if it isn't connected to the outside world at both ends and the wind going through could be fun on a cold winter night. Most of the straight sheds I remember visiting had a solid wall at the back end, often with a loco sized new patch of brickwork where someone tried to push a loco too many clear of the entrance points. I would move the shed to the right and put any outdoor pits to the left.

 

2) The two lines at the entrance are drawn crossing in a fixed diamond. How do you get the coal empties out and the Breakdown Crane in? The only way of getting into the shed is via the turntable. I think that the connection at the entrance needs to be a double slip.

 

Leamington GWR shed shows a practical layout of getting in and out and serving the coal stage/Turntable etc.

 

3) it is best if the turntable is kept separate from the other operations of the shed. I know it isn't your prototype but referring to Leamington again, the Ash Pit was positioned between the coal stage and turntable so a loco could be coaled or taken to the turntable via the other siding whilst one was over the pit. Ash from the pit and spilled coal was loaded into wagons in the siding between the coal stage and turntable access. They didn't have a crane to worry about so no siding there. In your case I would make the through road a siding off the coal stage road finishing short of the turntable stable the crane at the side of the shed make your breakdown crane siding a through road connected to the Shed road as far from the turntable as possible. Remember that two roads coming to the turntable is a recipe for one in the pit. 

 

 

A bit of a doodle got me to this layout.

 

There are some good photos of Leamington shed before opening and in use on this page.  https://www.warwickshirerailways.com/gwr/leamington-shed.htm

They show the relationship of the pits and some coal and ash wagons in everyday positions.

 

[Golden Eagle]

...and the good advice continues!

 

1) Re: shed "open at both ends": good point, well made...and probably a consequence of "copying other people's plans" without thinking them through!

 

2) Yes - the in/out diamond needs to be a double-slip. No idea how that...um..."slipped" past me!

 

3) Had to think about your "one in the pit" comment, until I realised that you weren't talking about ash pits anymore and the penny dropped (but better the penny than a locomotive!). Mike suggested converging all routes onto a single road to the TT. I can see the advantage of that allowing a locomotive to pass along ash pits, coaling...and then get out again if the TT was unservicable but another locomotive had pulled in behind. Would it be reasonable to connect the west end of the "ash siding" in to the end of the coaling road (as shown in the current draft)? I like the idea of leaving ash wagons there most of the time, but moving them if needed (e.g. for turntable failure or to allow for delivery of coal wagons - I've left the start of this road coming off the entrance road as I anticipate delivering a rake of 12 coal wagons, for which I need the equivalent length of two quad ST straights. However, I've moved the coaling headshunt south so that the yard pilot can actually back the wagons into that siding without having to pull back into the main in/out roads.

 

4) Both you and the Stationmaster suggested stabling the breakdown crane alongside the shed (the Stationmaster had this siding doing double-duty as a stores road). Would the crane just be shunted out of the way when stores were being delivered? Alternatively, there is now space for a dedicated siding for the crane, running parallel to the ash road (shown in yellow). Is there a prototypical reason for the crane to be stabled alongside the shed?

5) Does it matter which way locomotives enter the shed? (Almost all pictures I have found seem to show them "nose out", though that could be because the view is more photogenic!) Would a locomotive back into the shed, have the necessary work done, come out, be turned and then "parked" in a siding (perhaps a second head-shunt (green)?) while waiting for its next duty?

 

6) Am I right in thinking the engine shed floor consists mainly of inspection pits, in addition to those outside? (Thinks: why do something outside in the rain if it could be done inside under a roof...?)

[Flying Pig]

12 hours ago, Golden Eagle said:

Does it matter which way locomotives enter the shed? (Almost all pictures I have found seem to show them "nose out", though that could be because the view is more photogenic!) Would a locomotive back into

 

I'm sure I saw a reference to locos being stabled nose-in at Ferryhill when I was looking for information the other day, but I can't refind it.  It would make sense, as the shed faced north and most engines would be waiting to take up southbound workings.

 

The shed roads do dual duty for servicing and stabling, so your green siding is unnecessary.  If standing space was tight, perhaps more uncovered roads in front of the shed would be added?  Dont forget @The Stationmaster's reference to sidings for stores.

 

Also you seem to have sand and water set up as facilities on their own road like the coal stage.  Wouldn't water cranes among the stabling roads and sand distributed in a bucket be more likely?

 

Not sure what the leftmost crossover from the yellow siding adds operationally - things seem a bit busy in that area.

[TheSignalEngineer]

A problem with railway layouts is that there is very rarely one simple solution. Ask two signalling designers to signal a layout and you will get at least four ideas of how it can be done.

20 hours ago, Golden Eagle said:

I've left the start of this road coming off the entrance road as I anticipate delivering a rake of 12 coal wagons, for which I need the equivalent length of two quad ST straights. However, I've moved the coaling headshunt south so that the yard pilot can actually back the wagons into that siding without having to pull back into the main in/out roads.

 

I've altered the sidings in the middle so you can run a train in and run round without using the ash siding or turntable. I've kept the ash siding from the through line but you could take it off the coaling line. I've effectively created a through line from the slip at the coal bank headshunt to the turntable with the ash siding and your yellow siding connected to it then a kick-back to the shed area. 

 

20 hours ago, Golden Eagle said:

Is there a prototypical reason for the crane to be stabled alongside the shed?

The crane would normally be kept in a position where it could be got out easily when it was needed. When I worked at Saltley the crane was out to Washwood Heath and Water Orton on an almost daily basis so was kept on one of the roads near the outlet of the yard with some fire in ready to go. 

 

20 hours ago, Golden Eagle said:

Does it matter which way locomotives enter the shed?

Foreign engines would normally be stabled pointing towards their home shed when they had been coaled and watered. With home engines it could depend on if their next job was known or they needed a particular bit of work done on them in the shed.

 

20 hours ago, Golden Eagle said:

Am I right in thinking the engine shed floor consists mainly of inspection pits

The roads in the shed would usually have pits along the full length. Pits outside was a matter of fashion depending on company. A GWR straight shed like Leamington had an outside pit on each road. They would sometimes be paved alongside with blue brick or concrete.

 

Eric

Edited December 31, 2020 by TheSignalEngineer

[TheSignalEngineer]

Don't forget that you will also need siding space for a 'dead' engine or two either waiting attention, stored or withdrawn

[Golden Eagle]

20 hours ago, Flying Pig said:

I'm sure I saw a reference to locos being stabled nose-in at Ferryhill when I was looking for information the other day, but I can't refind it.  It would make sense, as the shed faced north and most engines would be waiting to take up southbound workings.

"Scottish Region Engine Sheds: 61 Group" certainly has a picture of a pair of A4s "nose-to-nose" in the Ferryhill repair shed. However, I have a feeling that aesthetics may ultimately take precedence over prototypical stabling (though it is good for that to be a conscious decision rather than one arrived at through ignorance!)

 

20 hours ago, Flying Pig said:

The shed roads do dual duty for servicing and stabling, so your green siding is unnecessary.  If standing space was tight, perhaps more uncovered roads in front of the shed would be added?  Dont forget @The Stationmaster's reference to sidings for stores.

 

With my "fleet" as it is (and "investment" in the short-to-medium term almost certainly being on track and scenery, I suspect I'm OK for standing space. I can sneak a short siding in to the south of the shed as an additional stores road or to hold @TheSignalEngineer's dead/withdrawn engine.

 

20 hours ago, Flying Pig said:

Also you seem to have sand and water set up as facilities on their own road like the coal stage.  Wouldn't water cranes among the stabling roads and sand distributed in a bucket be more likely?

 

Water cranes amongst the stabling roads is a given. I was thinking of a further water crane in the central area for use by locomotives which came in for turning only and did not visit the shed. If sand would be normally distributed by bucket, then I shall seek out some appropriately sculpted "men of the sheds" carrying such. That would allow the sand house to go anywhere convenient, as long as there is track for sand to be delivered  (I note that the Leamington sandhouse had its own short siding, presumably for delivery by wagon.)

 

20 hours ago, Flying Pig said:

 

Not sure what the leftmost crossover from the yellow siding adds operationally - things seem a bit busy in that area.

That was suggested as a "through road" to the TT, keeping clear of the sheds and the "service" roads for water and sand. I agree that it seems busy and I probably don't need both, though I was thinking of losing the middle crossover - once I've got the baseboards built, I may lay out both options and decide which I prefer. Retaining the middle track and removing the left would allow a longer "yellow" siding, for whatever benefit that might have...

@TheSignalEngineer for my education - why do you prefer the ash pit on the TT side of the coaling stage? Does the sequence of coaling and dropping ash matter?

I remain grateful for everyone's time and willingness to share knowledge! Happy New Year to you all!

[TheSignalEngineer]

2 hours ago, Golden Eagle said:

for my education - why do you prefer the ash pit on the TT side of the coaling stage? Does the sequence of coaling and dropping ash matter?

Doesn't really matter but it allows access to the coal stage without use of the turntable if a loco is in the process of having the fire dropped.

[TheSignalEngineer]

2 hours ago, Golden Eagle said:

That was suggested as a "through road" to the TT, keeping clear of the sheds and the "service" roads for water and sand. I agree that it seems busy and I probably don't need both, though I was thinking of losing the middle crossover - once I've got the baseboards built, I may lay out both options and decide which I prefer. Retaining the middle track and removing the left would allow a longer "yellow" siding, for whatever benefit that might have...

City sheds tended to be shoe-horned into impossible spaces and had much more track for the land area than other places. The key is whether the roads are needed operationally.