roundhouse angles for scratch-building in 00

[deepfat]

Hi 

I have got an adm turntable installed on my layout and my plan is to build a 6 lane round house around one side of it.  However I am not sure of the angles of the tracks e.g. 10, 12, 15 degrees between lanes.  I have about 450mm from the edge of the turntable to what will be the back wall of the round house and that looks comfortably long enough for a 4-6-2 loco like a Merchant Navy. In the attached pic I have simulated this with locos on Peco locolifts at 15 and it looks right.  Anyway I am sure there are experts out there who can help.  I did find a rudimentary laser kit here on ebay which is the sort of design I want and even that asks you to specify angles and to conserve space I'd prefer to be going with 6 lanes at 10 degrees.

Thanks in advance

Deepfat

Edited June 21, 2021 by deepfat

[melmerby]

Will this do?

St Blazey which has nine roads in about 90 degrees which gives a 10 degree track angle:

 

 

Edit: The turntable is quoted as 65' which should give it some scale

Edited June 20, 2021 by melmerby

[eastglosmog]

Old Oak Common in 1908 had 4 roundhouses with 28 roads each (including entrance roads) around the full 360, so average of 12.86 per road.  Plan seems to indicate that the spacing was not equal all round, though.

Edited June 20, 2021 by eastglosmog

[Harlequin]

Maybe go for a 4 or 5 road shed with the remaining 1 or 2 lines external. That might give you the flexibility to shorten the external roads, move the shed back and thus reduce the angles.

 

Lots of variables in play here!

 

[Dungrange]

I'm no expert on the subject, but I'd assume that the angle of the tracks in the roundhouse is dependent on the diameter (or technically the circumference) of the turntable.  If you have a large diameter turntable, then the angle between the roads can be less than if you have a smaller diameter turntable.

 

This then leads to how close the roundhouse is to the turntable.  The front of the building will have a pier between each track, so the smaller the angle between tracks, the further the roundhouse would need to be located from the turntable.

 

I think you therefore need to do what the real railway companies would have done and just see what fits best.  I don't think there is a 'right' answer to angle between tracks.  It's simply whatever was necessary to allow the desired facilities to be built on the land available.

[melmerby]

The St Blazey one I posted is the only segmented roundhouse on the GWR ststem at 1947 and was built by Cornwall Mineral Railway.

 

GWR standard roundhouses normally had 28 roads with a 65' turntable all under the same roof and one or two side by side except Old Oak Common which had four.

There were however other variations with Stafford road having 3x 20 road roundhouses, Swindon had 1x 28 & 1x 26 and others of 22 or 24 radiating roads, all are totally enclosed.

[Michael Hodgson]

If you want, you can get the roads quite close with this approach, although the trackwork isn't the simplest 

 

[deepfat]

Thanks all for the great advice and information. My comments to all those that replied are:

• the ADM turntable is based on the peco unit so 300mm diameter (74' at true scale). 
• If I take the st Blazey example (thanks @melmerby )  I'd estimate the roundhouse is about 30' from the edge of the turntable and the bay would be 80' long. That equates to 110' distance for the back of the roundhouse which isn't less from my planned 430mm (or 107'  at true scale).
• I would like 6 roads to create a sort of critical mass and it sounds like 10 degrees is OK based on the st Blazey example,  the key factor being how close the front edge of the round house is to the edge of the turntable  the bigger the distance the less angle you need to get the locos far enough apart form each other for servicing and pillars at the front to support the roof and doors. 
• My roundhouse will be based on this style at Eastbourne, but again it looks like this was only for smaller locos like terriers

Thanks again

[burgundy]

1 hour ago, deepfat said:

Thanks all for the great advice and information. My comments to all those that replied are:

• My roundhouse will be based on this style at Eastbourne, but again it looks like this was only for smaller locos like terriers

Thanks again

I don't have details of the length of turntable at Eastbourne when that photo was taken, but I would guess that it would have been either 42' or 45'. That was big enough for a 3 axle tender loco (Gladstones, G class singles and C class 0-6-0s). Extension bars were added to some turntables to cope with the Billinton 4-4-0s. The roundhouse that was built specifically for Terriers was at New Cross (the Rooter roundhouse) and the turntable there and the individual roads were just big enough for a Terrier.

Best wishes 

Eric 

[deepfat]

Thank @Burgundy and of course it was knocked down way before what I am running (merchant Navy's Schools, S15s etc ) were built so this is not going to be an exercise in replicating an actual building.  Also I am going to be building Hastings station as it was in 1934 and there was no roundhouse near there so I hope those who go for historical accuracy will forgive me.  and even worse I am not weathering my rolling stock and I am using Peco finescale track which may be a crime against history too.  Hopefully this will not mean my excommunication from this forum  

[Joseph_Pestell]

4 hours ago, deepfat said:

Thanks all for the great advice and information. My comments to all those that replied are:

• the ADM turntable is based on the peco unit so 300mm diameter (74' at true scale). 
• If I take the st Blazey example (thanks @melmerby )  I'd estimate the roundhouse is about 30' from the edge of the turntable and the bay would be 80' long. That equates to 110' distance for the back of the roundhouse which isn't less from my planned 430mm (or 107'  at true scale).
• I would like 6 roads to create a sort of critical mass and it sounds like 10 degrees is OK based on the st Blazey example,  the key factor being how close the front edge of the round house is to the edge of the turntable  the bigger the distance the less angle you need to get the locos far enough apart form each other for servicing and pillars at the front to support the roof and doors. 
• My roundhouse will be based on this style at Eastbourne, but again it looks like this was only for smaller locos like terriers

Thanks again

 

You would get something rather bigger than a Terrier in there, but probably nothing bigger than a 4-4-0 of which the LBSC had a lot..

 

But many roundhouses had extensions on the back as locos got bigger, sometimes rather ramshackle. These would often be on only some of the roads depending on the land available.

[Michael Hodgson]

28 minutes ago, Joseph_Pestell said:

But many roundhouses had extensions on the back as locos got bigger, sometimes rather ramshackle. These would often be on only some of the roads depending on the land available.

That sounds rather like the practice of putting too long a train into the refuge siding and propelling the stop blocks before getting the PW gang to reconnect it by inserting the missing rails !

[deepfat]

I remember having to bodge workshops and hangars when Challenger replaced Chieftan so I get the comments about tanks in sheds

[melmerby]

4 hours ago, Joseph_Pestell said:

 

 

But many roundhouses had extensions on the back as locos got bigger, sometimes rather ramshackle. These would often be on only some of the roads depending on the land available.

The central three roads at St Blazey went into the square building behind the "roundhouse" and were much longer.