turntable track spacing


gregc

gregc

Apprentice Modeler
i'm looking for information on turntable track spacing, both for a roundhouse and parallel tracks. nothing large, just 2 or 3 stalls

it seems that roundhouse tracks are 10 degrees apart. but how far from the turntable would the roundhouse be located?

the other option is an engine house with parallel tracks. again, how far from the turntable could such a house be located?
 
This can be a tough one, because the railroads had to deal with space available, economics, ease of construction, etc. Our club is struggling with this right now for a large roundhouse. Since you seem to be a Reading guy what with that brass camelback and all, I'd recommend you check out some books on the Reading, and what they did. Maybe you can find a smallish engine facility to base your terminal on. You may also have to yield to selective compression to make everything fit. Track spacing varied with number of stalls, size of power, etc. There was a big difference in the layouts of Mission Bay roundhouse in The San Francisco area that serviced everything up to and including 4-8-8-2's and the Port Costa roundhouse which was a division point and handled mostly 2-8-0's. Photos of the prototype you want to emulate are a must for a good scene.
 
Drawing it to scale in several versions would be your best bet. The problems are numerous. What will be the diameter of the turntable? The bridge length affects how much of an arc is necessary to yield separate radial bay and servicing tracks. What will be the dimensions and the separation between bay door frames? That, in turn, affects how far the doors must be from the lip of the turntable pit. And so on. It all has to come together...pit diameter commensurate with bridge length, sweep of arc to get distinct radials that diverge at optimal angles to run bay tracks centered in bay door frames of a given dimension set back a given distance from the pit of the turntable.

So, you have to draw it out in scale to see how it will all work for you. If you elect to use commercially available components, the manufacturers have it all worked out to fit.

-Crandell
 
i had thought this would be a common problem. I want to plan the layout with a turntable, but i don't know what structures i'll use. After thinking about this, i concluded that 2 or 3 stall roundhouse with straight track from the turntable would probably require too much space. I also don't know what the door spacing would be.

A 2 or 3 stall engine house (with parallel track) is probably more practical, but the door spacing is still an unknown (thought probably 2"). However, i was wondering about the curved track radius for (presumably standard) 10 degree track radials that result in 2" parallel track spacing. Through trial and error i figured it to be 60", but the house is nearly 12" from my 90' turntable. (see figure) curved tracks would be on both sides of straight track. The figure shows track for 5 stalls.

I guess some simple eyeballing and not using 10 degree radials would bring the house closer to the turntable. i had hoped to find a web page discussing this.

Thanks for the help
 
Greg, it was common for roundhouses to have curved track leading to the stalls. This occured because there wasn't enough space for the typical half-roundhouse or because of changes and additions through the years. You can use flex track to lay the track from the turntable to the roundhouse. You would have to keep the roundhouse far enough way from the roundhouse so the curves aren't too sharp but the way you have is shown in your drawing looks fine
 
I had to curve the two outer bay radials of necessity due to a slight mismatch between my commercial kit roundhouse and the Walthers 90' indexed turntable.

IMG_2129cr.JPG
 
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