# What is distance between tracks to avoid collision?



## Russty (Aug 7, 2010)

*I am building a 11 1/2" wide shelf to go aroud a 10 1/2' by 26' room and want to run 2 tracks on it. My curves around the corners will be 8' diameter and the big trains I want run require a minimum 8' diameter curve*. *How far apart must the tracks be, especially in the curves, to avoid collision? Non technical answers would be appreciated. Thank You! Pete*


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## kormsen (Oct 27, 2009)

i do use 16 centimeters width (6.3 inches) for each track on straights. 
in curves i do add one more inch per track. 
.


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## aceinspp (Jan 2, 2008)

6 1/2 for tangent and then depending on the two diameters of the curves one can use 7 1/2 but you fail to tell us what type of equipment you will be running. Later RJD


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## blueregal (Jan 3, 2008)

Don't know about distance between I believe 7 1/2 inch is good, but I wouldn't go any smaller than 10ft diameter curves especially if you intend on running some bigger engines. !0ft diameter period!!! NO smaller I wish I would have went 20ft out on my outdoor layout!! Regal


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## Russty (Aug 7, 2010)

I have Aristo-Craft (22.5 degree arc/8 foot diameter) curved track at the 4 corners of the room. I would like too run a USA Trains J1e Hudson Steam locomotive 1:29 scale 40.5" long on one track and a USA Trains SD40-2 diesel 1:29 scale 26.75" long on the other track. Is the distance between the parallel tracks measured from: End of ties to end of ties? Between the outside rails of the parallel tracks? or between the middle point of the tracks? I presume the extra inch distance between tracks would start when the curve begins. Would the equipment mentioned work or would I have to get smaller trains? Thank You for your help.


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## Anthony Duarte (Dec 27, 2007)

You also need to keep in mind that for the curves to be parallel, they have to be different diameters - the inside curve being tighter than the outside.


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## krs (Feb 29, 2008)

Track distances should always be measured centre-line to centre-line - that applies to the diameter or radius as well as tracks running parallel.

For parallel curves, the distance doesn't just depend on the length of the equipment but also on the position of the bogies and the overhang of the equipment as well as the scale (obviously).

If you have the track and the equipment, the best way is to just try it out. I like to keep parallel tracks fairly close together - I find it's more realistic hat way.


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## Mike O (Jan 2, 2008)

Russty, 

if you have the engines and have the curve track, you might want to try this: 

Lay down some newspaper. On it place about four feet of the 8' diameter curve you have. Place the engine on the track. In about the middle of the engine on the inside of the curve, put a mark on the paper where the overhang is greatest. That mark will give you the overhang of the engine on the inside of the curve. Then do the same for the corners of the engine that are on the outside of the curve. That will give you the outside overhang. Remove the engine and measure the distance from each of the marks to the center of the track. Use the largest number. It will probably be between three and four inches. Double that number (for two tracks) and add a half an inch. That will give you the distance needed between the tracks on the curve. If you are going to run any very long cars, you might do the same with them. As Anthony pointed out the distance will be different for the inside and the outside curves because of the different diameter, and as KRS indicated the location of bogies (trucks) under a long car will make a big difference in the overhang. 

Hope this helps. 

Mike


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## Russty (Aug 7, 2010)

Thank you for your ideas, they are thought provoking. I now tend to go for only 1 track on a 11 1/2" wide shelf. This would leave room for scenery/buildings all the way around the room, especially in the corners. What size Locomotive can negotiate a 90 degree curve of a 22.5 degree arc (8 ft diameter)? Are there any guidelines?Manufacturers are not very clear about what their products can negotiate and I don't want to buy a train and find out it is too large to make the curve. 
I have a room (finished garage) with multiple N scale, Z scale, and yes T Gauge trains along with 400 Diecast and Model cars in display cases (50 space ships too) on the walls. The G scale train would look great since I have a 12 foot ceiling.


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## Tom Bray (Jan 20, 2009)

I have an MTH 1:32 F7 and a Hudson. Both work fine on 8' diameter loops and look reasonable. The freight cars also function and don't look too out of place. The passenger cars don't look right going around an 8' loop because they are just too long, they may also derail easily. I don't think an engine larger than the Hudson would look appropriate on an 8' curve. Also the LGB streetcar looks fine on an 8' loop, plus they were designed to handle fairly small radii curves in real life. 

I think the size difference going up to 1:29 may look less prototypical on 8' curves but I think I saw several diesels that were rated for 8' or smaller curves. 

Of course Eggliners and the HLW Macks all work fine on 5' diameter curves. Neither are particularly prototypical though. 

Tom


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## eroc731 (Aug 4, 2010)

Russty it would appear we are kindred spirits...I too have both N and G gauge in the same room....about 4 years ago I re-did my basement and did a custom soffit railway. My buddy is an architect and worked with me to design and then build the basement. My soffit/shelf is 10" deep and I run 8' curves. I have mostly short wheel base locos but do have a set of stream liner passenger cars that will run on it but overhang is not prototypical...what I can say is that the 10" deep shelf/soffit is NOT wide enough for two tracks, ( I tried) but it was would fit in my room and with the custom cantilever soffit we designed. My edges and the back wall are "curved drywall" in the corners. 
I think sticking to one track is the way to go unless you can get the extra room. BTW my track is about 1.5" from the edge of the soffit. If you e-mail me at [email protected] I can send you pics as Iam unable to share them here...

Another neat feature was I made a cut-out as you walk down the steps so you can be at eye-level and see the whole loop and it also gives me a place to switch out locos and rolling stock. I had posted the layout here but it was before the server was migrated and I can not seem to find tghe original post....


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