Part 4

Layout design for realistic operation

by Harry and the late Ivor C. Marshall.

© Harry Marshall 2006

The right of Harry Marshall to be identified as the Author of the Work has been asserted
in accordance with the Copyright, Designs and Patents Act 1988.


Steam Era Motive Power Depots

Now a word or two about locomotive servicing for those not familiar with the era of steam. Steam locomotion requires basically three essentials. A lot of coal, a lot of water, and some means of disposing of ash, etc. Of these, the imperative, always, is water. Therefore, the first thing a driver would be needing during or after a journey would be access to a water column. Next, the coal supply would need replenishing, and thirdly, disposal of ash from the under-fire pan. At the end of a diagram, there would usually be need to clear the smoke-box of accumulated soot or char fragments (lovely job!). After this would come the oil-round and inspection, before the next duty. It follows that a locomotive depot should ideally be laid out to accommodate this set of requirements and priorities, and the two designs figures 10 and 11 are presented with this in mind. It is important to remember that, just as in a goods yard of any size, almost all internal movements are made without control by a signalman; signals would control entry and exit only, and there can be any number of machines in steam and able to move at any time. It therefore follows that the layout of the facility should so far as possible ensure an orderly progression from one resource to the next, to minimise conflict or collision.

Most depots, and almost certainly one associated with a terminal station, will require a turntable. On a model this could form the access to the shed, as well as performing its main function. There also needs to be a pit road and ash dumping ground, as well as a coal loading point, either a stage, crane or coal hoist. Water columns should be present at both the entry and exit roads (don’t forget the water tank!), and accessible from as many roads as possible. Preferably, the coal needs to be available just prior to the turntable, so that a locomotive could be berthed in the shed or sent out to traffic again fully supplied. The coaling point needs a siding to it, so that incoming supplies can be off-loaded. In the model, the ‘coal empties ‘ could be pushed forward to be ‘loaded with ash’ from the ash pit area. Not many of us will have the space to do it, but an elevated coal road, leading to a coal elevator and mechanised coaling facility makes an impressive and unusual model. The larger of these two designs includes a by-pass road for any loco that has to be turned and watered only, clearing the access to the depot for other machines with greater needs. Another means of increasing the efficiency of a depot is the provision of ‘parking’ roads near the exit and water columns so that outgoing locomotives can be strategically placed to suit their order of departure, not necessarily the same as the order of arrival. The loco foreman’s office (and driver’s bothy) needs to be in this area, so as to deal with changes of plan readily when required.

Very few models are likely to need it, but the layout of the depot in figure 10 has been made with the possibility of parallel ingoing and outgoing movements in mind. A busy club terminal layout could just be intensive enough to make this worthwhile, but it reflects reality in many locations around the country in the heyday of steam. The other figure is at the other end of the scale, a bare minimum set-up for a small layout at a provincial terminus.

Figure 10

This is a very flexible design for a steam locomotive depot, which could be used with one of the previous station layouts, or simplified to suit something smaller. Again, intended to fill a corner, but by re-arranging the main lines outwards, it could become a principal feature along a wall.

Figure 11

A “bare minimum” design for a small steam shed. Both this and the previous figure are idealised forms; it was rare for the real thing to be quite so convenient!


In Conclusion

This series of articles started with the suggestion that layout design, or redesign from reality, needs to be done with a very clear view of the expected and required operations to be carried out at the station(s) on a layout. That is to say, take the commercial view, and ask “What do (did) the customers want from their railway?” Once there is an understanding that the railway must meet the needs of the community it seeks to serve, then geography can be considered, and a study made of the operating methods in use at the time the model is to represent.
Putting it another way, don’t start with the trains, start with the world they will live in.

Along the way, the idea was presented that a finished design could be built up in stages, if resources prevented it all being done at once. The key point is the need for a clear operating design view of the complete layout, really before any track is laid at all.

If these ideas have done anything towards encouraging this kind of forward thinking, offered more satisfying modelling, or even just put another perspective on layout design for someone, then I shall be well pleased, and I am sure my father would have been, too.

Happy modelling,

Harry M

PS I should like to record my sincere thanks to Nigel Godsell for the considerable time and effort he has put in to make this material presentable for the Weymouth MRA website.


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