# roundhouse



## caferacer (Jul 22, 2010)

Hi I am currently planning my layout I would like a large roundhouse and turntable I do have plenty of room and can fit a 2 m or a 6'.5" turntable with 1.5 m or 4.'9" out side bay per line and then a 1.5m again 4'.9" line inside the roundhouse to house all the locos,with the roundhouse at 220 degree end to end.
My question is what distance do i need to keep betwen tracks for the inside lines inside the roundhouse for locos to run in and out on and how many lines can i fit inside to be both correct and to look the part as I am just starting out in g scale any and all help caferacer.


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## Semper Vaporo (Jan 2, 2008)

Posted By caferacer on 24 Jul 2010 08:02 PM 
Hi I am currently planning my layout I would like a large roundhouse and turntable I do have plenty of room and can fit a 2 m or a 6'.5" turntable with 1.5 m or 4.'9" out side bay per line and then a 1.5m again 4'.9" line inside the roundhouse to house all the locos,with the roundhouse at 220 degree end to end.
My question is what distance do i need to keep betwen tracks for the inside lines inside the roundhouse for locos to run in and out on and how many lines can i fit inside to be both correct and to look the part as I am just starting out in g scale any and all help caferacer.



I have gone though these calculations, but it has been a while, so let me lead you through the steps and you can pick your dimensions to fit your space and wallet.

1st, I think your turntable is HUGE! Are you sure you need a 2 meter turntable? I think that even a USAT BigBoy would be dwarfed by that, but I am not real sure of what its length is. Also, the Roundhouse Stall would need to be slightly longer than the turntable to give room for the workmen (with heavy tooling) to move all the way around the engine in the Roundhouse stall.

Anyway, sum the various dimensions you have specified to get the diameter of the roundhouse...

Turntable + Apron times 2 + stall length times 2 or 2m + 1.5M + 1.5M + 1.5M + 1.5M = 8 Meter diameter, (26-ft. 3-in.)

How wide should the doors be? (Plus the spacing between the doors [door-frame]?) Lets assume it will be "about" 6-in. total (5.25 in. plus 0.75 in, for the frame between stalls).

The circumference of the inside wall will be: Pi * Diameter:

Pi * (Turntable + Apron * 2) or Pi * (2 M + 1.5 M + 1.5M) = Pi * 5 Meters = 15.7 meters.

Divide that by the door width to get the number of stalls possible in a full circle RH.

51.5 ft / 6 in. = 103 stalls... (My editorial note: that is WAY too many.)

If you are planing only about 220 degrees of Roundhouse then you would have 220/360ths of 103 or about 63 stalls (slightly over 220 degrees). (Editorial note: You got THAT MANY locos?)

The spacing between the tracks will work out to whatever they work out as when you center the track in the stall doors. But you want to avoid having the tracks cross when they near the Turntable (some prototypes did have this situation and put frogs at every place where the rails crossed!)

Let's reduce the lengths a bit to something a bit more reasonable (to me, at least).

Make every dimension 3-ft; turntable, apron, stall length and you get a 15-ft diameter Roundhouse.

Keep the 6-in doorway width and you get Pi*9-ft/0.5-ft = 56.5 stalls (oops, don't want a half stall!, so juggle the doorway width, or just assume it will never be a full 360-degree building.)

So taking the second option, you want 220/360ths of 56.5 stalls = 34 or 35 stalls (it came out to 34.55 stalls). Still lots'a stalls, but much more realistic.

Even if you expect longer engines than 3-ft (1 meter?) you can just shrink the apron width to make the Turntable a bit longer and expand the stall length a similar amount and if you keep the inner diameter (circumference) of the RH then the rest will just fall into place.

Be sure to verify my door width assumption! What scale are you intending this to be? Prototype doorways were usually 14-ft wide by 17-ft high. My 6-inch door dimension is for 1:32 scale, but would be much too narrow for 1:20.3 scale.

If you redo the math with your scale doorways, you will get what you need.


May I suggest you get Google Sketchup? If you do, I have drawn a Roundhouse based on the 3-ft standard dimension, that maybe you could glean some info from (you will need a really good PC to view my drawing because I got way carried away with detail in the track and it takes a long time to render the drawing when I shift the viewpoint and it is quite frustrating to work with on a slow PC!) My drawing is NOT detailed enough to start cutting parts! It is just flat walls to show the relationship of the stalls, track and turntable.


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## caferacer (Jul 22, 2010)

Semper firstly thankyou thankyou thankyou wow maths was never my strong point will work out now to your measurments . 
My 2 mtr 6 foot turntable was worked off the BigBoy at 1.28 m or 50.1/2 inches and the 2-6-6-6 at about the same length also the Dash 9 at 749mm or 29.5 inches I would like to have had a couple of double header Dash 9 which means i could get both on the turntable ,apron,and in the roundhouse stalls at the same time. 
Any way you have given me a start to work towards once again thank you caferacer


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## Semper Vaporo (Jan 2, 2008)

Talk about rusty at math... Hee hee hee, you have no idea how long I worked at drawing a Roundhouse before I began to understand which dimensions are the critical ones to hold stable and then let the others just fall into place. The width of the doorway is probably the first one to pick, then the turntable length to hold your longest engine (dunno about two at once! I don't think that was ever prototypical practice, but that doesn't prohibit you from doing what you want... this IS a hobby, afterall!). Then, just for symetry I made the apron the same length and the stall length the same, too. I was shocked when I realized that made a 15-ft diameter building! 

My track is all elevated as two teardrop shaped loop-backs connected together with about 18 ft of track (making a 50-ft straightaway). The loopbacks are 16-ft in diameter, so the building will completely FILL the space inside... that translates to a 16-ft diameter "deck"... I priced a 16-ft diameter deck and was shocked at what I would be paying just in lumber.

Still, I want a 3/4 Roundhouse! Here are some images captured from the SketchUp drawing I did. 48 stalls! To see it all, you lose all detail! There may have been only 2 or 3 ever built this big in the real world. I did play with the turntable and stall lengths a bit, so the 3 measuremens are no longer exactly 3-ft, but the inner diameter is still 9-ft.


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## caferacer (Jul 22, 2010)

Semper Vaporo great drawings and again thanks for the help going with the turntable at 1.5 metres ,apron at 1.5 mtr,and stalls at 1.5 as well with about 32 stalls or 180 degree round house,the 1.5 will carry my Bigboy and other large steam locos and a single Dash 9 to look the part. 
Have placed the name Semper Vaporo on the roundhouse building in honor of your help some another item is named the build will be some thing else I use to build model ships for museums so this round house will be a piece of work for all to see and again thank you caferacer.


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## Semper Vaporo (Jan 2, 2008)

Posted By caferacer on 25 Jul 2010 04:00 AM 
Semper Vaporo great drawings and again thanks for the help going with the turntable at 1.5 metres ,apron at 1.5 mtr,and stalls at 1.5 as well with about 32 stalls or 180 degree round house,the 1.5 will carry my Bigboy and other large steam locos and a single Dash 9 to look the part. 
Have placed the name Semper Vaporo on the roundhouse building in honor of your help some another item is named the build will be some thing else I use to build model ships for museums so this round house will be a piece of work for all to see and again thank you caferacer. 

I am deeply, deeply touched







(**) that you'd name the building "Semper Vaporo"... Thank you very much.







I am honored!

But be prepared giggles







from anyone that can translate Latin and then sees a Dismal, err, uh, Diseasel, err... Diesel (***) on the turntable!

Semper = Forever, eternally, with no end.

Vaporo = Steam in transistion, water vapor moving, steam working.






** Some folk say I have always been a bit "touched" in me lil' punkin' haid!

*** Rudolf Diesel... akin to Simon Legree, Snidely Whiplash, Darth Vader and other Dastardly Villans.


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