Maximum Wagons Length In Goods Yard Sidings

[steaming_chris]

I’ve tried to be proactive and searched the Prototype forum first, alas I can’t find what I’m looking for, so I’ll ask for help from the experts.

 

(I apologise if my terminology is wrong)

My period and region of interest is BR (WR) in the early ‘60’s. I’m aware that on the mainlines in this region that between “blocks”, if that is the right term, that long goods trains to be held in passing sidings would be between 30 to 40 wagons long, plus loco and brake van. In starting or terminating yards, such as Avonmouth Docks what would be the approx. size of exchange sidings there ? I would assume to allow for sorting (though probably already sorted by the PBA) that 50 wagons per siding would be approximate ?

I would welcome comments and suggestions

[jwealleans]

My thoughts would be that the reception sidings would need to be as long as the longest train to arrive - the rest would be as long as space allowed.  Depending on the route a departing train was to take the line limit might vary quite widely, so one direction might only need space for 35 whereas 70 or 80 might be allowed in another.  If a yard was constricted, siding length might determine the maximum train received or dispatched rather than line limits.

 

From a modelling perspective more shorter arrivals and departures might make a more interesting model to watch and operate than less frequent but much longer trains.

[Miss Prism]

Possibly a sweeping generalisation, but the usual maximum for many GWR loop lengths was approx 70 wagons.

[The Stationmaster]

What you are talking about is called a 'Length Limit' and in BR times this was expressed in SLUs (Standard Length Units, an SLU is 21ft to be exact) the GW system was somewhat more complex but boiled down to much the same thing with the expression '= X' where X was the number of ordinary wagons, longer wagons were noted as 'X+' etc.  

 

So that's how we measure length - and train length excludes the engine and, in some cases, the brake van because they are there all the time so there's no need t account for them.  Each section of route has/had its own Length Limit, usually this was dictated by the shortest running loop or refuge siding.  Any marshalling yards on that section would be capable of handling trains up to the Length Limit although quite possibly they might only have a few sidings which could take trains of that length.

 

I agree with Jonathan about the approach from a modelling viewpoint - to which I would add that in the real world, as in the model one, shunting longer trains is more awkward and time consuming than shunting short ones.

 

edit to correct typo

[The Stationmaster]

Possibly a sweeping generalisation, but the usual maximum for many GWR loop lengths was approx 70 wagons.

A fair assessment I think for many routes.  However to be pedantic it would be a loop capable of taking a =70 wagon train, plus the engine, plus the brakevan.  So the actual length was rather more than that of =70 wagons.

[Fat Controller]

The yard you need to be looking for details of is St Andrew's Road, I believe. This was between St Andrew's Road station and the Dock Estate; it was accessed from St Andrew's Junction at the Avonmouth end (chainage 16m.00ch) and from Holesmouth Junction at the Severn Beach end (chainage 14m 66ch). My recollection of the place in the mid-1970s, when I worked nearby, was of about ten or more parallel loops. My impression was each would hold perhaps 50 or more 4-wheel wagons (50 SLU; Standard Length Unit, based on 17'6" over headstocks, still being the norm for measuring siding capacity, despite such wagons being extinct for a couple of decades now).

There is at least one person, River Cider, on here who probably has the gen to hand, as he worked in the TOPS office at Bristol at about the same time I worked in Smoke Lane.

If you're interested in Avonmouth and its surrounds, then the relevant R A Cooke volume of 'Track Layout Diagrams of the Great Western Railway and BR (WR), 19B, is worth seeking out, as this will show how the layout has changed over the years.

[steaming_chris]

Thank you to everyone for your valuable knowledge, I do appreciate it.

Regards

[The Stationmaster]

Access to the main nest of Corporation Lines sidings for the GWR was at Holesmouth Jcn at one end and at Avonmouth Goods Yard signalbox for the other end.  Although the Corporation Lines ran throughout the LMS sidings were accessed from the St Andrews Jcn end as they only faced in one direction (towards the LMS).  The Corporation Lines ran through to Gloucester Road Jcn and there were further sidings beyond that to Avonmouth Dock Jcn - all very complex.