I'm thinking about doing a small ON30 layout in a large coffee table I have. What would the minimum diameter I can use just to run a small switcher or rail truck in ON30? Thanks.
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Depends, of course. When you say "small switcher", what do you have in mind? A two-axle Plymouth or Porter, a 4-axle GE 44-tonner?
Commercial HO track radius is defined at the center line. Atlas and Bachmann both make a 15" radius (30" diameter at the track centers) that limits rolling stock and reliable operation to the very short, very few. We (LHS) suggest adding 4" (2" each side) to the diameter as a guide to the minimum table dimension to accommodate. For instance, the popular HO radius of 22" was created to fit the 4-foot width of a 4x8 table (44" diameter + 4" = 48")
Nonetheless, if you stick with 2-axle engines and rolling stock, you might be able to go sharper. But you'll need to experiment with this using flex track, and flex track will be pretty much your only option for achieving the smaller radii on your final layout plan. BTW, traction layouts (trolleys, street cars, even interurbans) typically use VERY sharp radii curves; its certainly doable.
Re coffee table layouts... We (LHS) get inquiries about this, mostly from people who feel N scale is the perfect option for this. However, a couple of our customers reported back that, although the concept was great, the reality was very disappointing. The first PITA mentioned was frequent derailments and structure/scenery damage from table movement, bumping, shifting, etc.. It's what coffee tables experience, in general.
Now, I know in one situation the customer didn't help by making it exceptionally hard to get to the layout for maintenance and repair. He had, perhaps, overthought the security issue...multiple screws accessible underneath by lying on the floor holding a flashlight. The other customer, however, simply was put out to remove drinks, snacks, magazines, other paraphernalia that seemed commonplace on a coffee table in order to lift off the table top and make such repairs/re-railings...which were "all too often".
Bottom line,....think it through. Consider how the table will REALLY be used...by everyone in the family as well as guests. Then, if it still seems a good option, do some experimenting regarding the radii, equipment, etc..
Just some thoughts, FWIW.....always.
KD
You may find this guide helpful.
Way back when I had a loop of O-27 in the space I'm talking about. I wouldn't be running anything larger than a 44 ton switcher.
What we have found is that we have very little issue with any of the commercial engines, its the rail cars that have been giving us fits! The cheap ones run fine! The ones with all the super details can't stay on the track on any kind of curve! NUTS! We have had to go underneath ALL of them and do some 'pruning' of just a little bit of those details so that the trucks can at least turn and swivel. So far we have NOT had to add any weight although the flats are just a little on the light side. We are using ME code 83, #5 switches, 2% mainline grade and roughly 30 plus inch radius most places. Remember though that ON30 while small for O scale are large for HO so they still need some looking after on very tight radius layouts. The smallest I've heard of was 12 inch radius but most are 18 to 20 inch radius. Have fun! Russ
