HO scale and 15" radius curves

Discussion in 'Track Planning' started by elwood, Jul 7, 2005.

  1. elwood

    elwood New Member

    I just made some extra space in a spare room in my apartment. The biggest layout that will fit in the space is 32" x 60". I figure I can get away with using some atlas 15" radius snap track, but I have a couple of questions. I just picked up one of those Bachmann EZ command DCC kits with the loco (GP-50) and some short rolling stock. It's time to get my feet wet with DCC. All have the EZ mate/ kadee couplers. First, will this loco be able to make the radius? and two, will the couplers stay together?
    I really dont want to make a switching only shelf layout, I'm a continuous running kind of guy. I know there won't be much room to spare on the outside of the track, so I plan to make a "guardrail" of sorts out of crown moulding to keep any funny business from happening. I currently have a 2x9 continuous running HO layout in another room, but I'm getting tired of having to heavily modify stuff to run on it, not to mention it looks bizarre doing it! If this is not possible, I may have to move to a 2x8 switching layout, in that case, post some plans if you have any.

    I'm tired of N scale....I'm sorry, I tried it and it just wasn't for me. I don't know how my grandpa spent 20 years with it.

    Thanks for the advice, you guys sure have helped out in the past!
  2. SAL Comet

    SAL Comet Member

    Ha Elwood, I did some testing a while back with 15" curves. I set up a half circle of 15" R. track and used flex track to make an easment into and out of the turn, forming a teardrop shape. My Bachmann GP50 would pull about fifteen (or push 12) 40' cars through the curve without derailments or uncouplings. Any more and the loco would loose traction. Keep in mind that was with no turnouts to contend with. That said, 32"x60" is only enough room for a very small oval with a short siding on each straight, which to me would get old fast. How did you get a continuous run in 2x9?
  3. elwood

    elwood New Member

    To get the continuous run I used flex track, one piece at each end of the layout.

  4. pgandw

    pgandw Active Member

    I understand where you are coming from. I'm torn between a 4ft x 75in layout (as big as will fit in my Explorer) and 2 shelves linked together as an L, one 18in x 8ft, the other 18in x 80in (each shelf in 2 sections). If I build the table layout, I'm probably going to be forced to move it into and out of a corner on casters. I'm afraid the rolling stock will be knocked over each time I move the table or the table gets knocked by the kids. And the wife would much prefer the shelf approach with integrated shelves. But the lure of continuous running is very powerful.

    I will probably end up with the shelf layout along with a test track/run-in loop (about 4ft x 40in) that can be stored against a wall. And it will have both 15 and 18 inch radius curves on it to test my kit building skills.

    As a general rule, earlier protoypes (and models) did better going around 15in radius curves in HO, especially models made in the 50s/60s. Small steam locos up to small 4-6-0s and 1st generation diesels (overall length less than 60ft) would be your best bet. I would stay away from cars over 40ft scale length. You may (but hopefully won't) have to switch to truck-mounted couplers on both engines and/or cars to get the needed perfomance, although backing ability will suffer in that case. But reality is anything longer than a 4ft train (engine, 6 cars, and caboose at most) is going to overwhelm your layout - you might even find a 4ft train to be too much. You can find the older stuff - often in unbuilt kit form - at some hobby shops, E-Bay, shows and the like. Bringing the older stuff up to current standards is a fun pastime in itself.

    It will be more of a challenge to install the DCC decoders in the smaller locomotives, and room for speakers for onboard sound is highly unlikely (but you could easily hide speakers in the scenery on a small layout). Nevertheless, I see lots of room for fun if you let the limitations become your opportunities.
  5. elwood

    elwood New Member

    thanks for the replies...

    I'm now having a problem with a plan. I've been looking at so many plans lately, that my mind is boggled. Would anyone like to share a track plan? Your help would be greatly appreciated! I have about 3 industries to work with and I need a spur to store some short passenger and frieght equipment.
  6. pgandw

    pgandw Active Member


    A couple of thoughts came while thinking about the fellow's 15.5 inch guage minimum radius question. I once heard - don't recall where - that the minimum radius for a piece of model equipment was generally about 2 to 2.5 times the car or engines length. Of course, your mileage may vary, and toy trains do better than this. But all my observations of HO and N seem to come pretty close to the rule. Atlas must have thought so when they built their turntable at 9 inches for their standard 18in radius track. Many modelers have cursed Atlas for making the turntable only 9 inches, but I've yet to see anything bigger than 9 inches successfully use 18in radius curves, except for a few articulated steam engines, or specially modified locomotives. Only 60-65 ft passenger cars (just under 9in long!) work well with 18in radius.

    Going to 15in radius limits our length to 7.5in or 55 scale feet without the special mods you described in your opening (less for more highly detailed, less modified models).

    As for track plans, given the width, minimum radius, and length, the only possible continuous run is an oval, a "slightly squeezed" oval, or a figure 8. A twice-around cannot be done because of the width - absolute minimum width required would be 36in for 15 in minimum radius. Minimum length of a 90 degree crossing figure 8 with 15in radius would be 50in - formula is circle diameter plus 1.33 times min radius for the straight.

    With a 60in length overall, you have 26 to 28in "straights" on each side of the oval, with about 10 in additional at each end inside the oval. Because of these short "straight" segments and nothing to spare width-wise, a traditional run-around or passing track attached directly to the oval is pretty much a non-starter. The oval becomes your run-around track for switching moves, unless you incorporate your industrial spurs into a run-around track. Just remember to leave at least 8 inches beyond the turnout at each end of the run-around for your locomotive to get by.

    I could see at least 2 industrial spurs on each side of the oval going into the middle and ends of your space. For switching interest nearly half your spurs should face each direction of oval travel. At least one should have a switchback entrance. The switchback "lead" must be at least 14 inches long (one car plus one loco). At the same time, I would avoid too much symmetry between the 2 sides of the layout. In fact, a center backdrop could help divide the layout into 2 scenes.

    I like to use the Atlas computer track planning software (free) as a check on my ideas. By using the Atlas Snap Track libraries, you know your plan will fit in the space, no matter what. You can usually squeeze things a little by cutting back the switches and using flex track, so if the software plan fits the space, I know I have a feasible plan that won't be too crowded or impossible to build.

    Are you sure you can't get any more width? I have a plan for an HO/HOn3 layout that fits a 46in x 60in space. Even a few more inches of width (say 36in to 40in) would let you do twice-around or expand your min radius or incorporate switches for a passing track into the end semi-circles.

    Hope this helps.
  7. cidchase

    cidchase Active Member

    Hi elwood,
    Here's a rough layout suggestion with a central operating bay that
    lets you use larger radius curves and makes use of the space around
    the layout which would otherwise just be clearance. The front folds
    down (or up) and rolling stock is left on the back half. This kind of thing
    has been showing in the mags lately.

    Adjust to fit :D :D :D

    Attached Files:

  8. elwood

    elwood New Member

    I forgot about the folding idea. What do I use to connect the track joints? Small piece of track? I guess I could use a long piano hinge to connect the 2 boards.
    Thanks for the suggestions!
  9. pgandw

    pgandw Active Member

    Great idea about folding a section! However, I strongly recommend the section fold up, not down. Folding up has the following pros and cons:

    Pro) You duck into the operating area under the folded section instead of stepping/climbing over the folded down section. Far less likely to kick the folded section, and permits the layout to be at a much higher height. Stepping over more than about 2 ft high is pretty difficult for some.

    Pro) The finished layout section is somewhat protected in the up position. Other room occupants will have greater difficulty kicking, banging into, or just plain handling your scenery and structures.

    Pro) You can easily reach the underside of the folding section for wiring and the like. You can also cover it with decorative paneling, bulletin board, or whatever you want.

    Pro) The rest of your layout is partially protected by the folded section.

    Pro) Ceiling tie(s) can substitute for a folding leg arrangement.

    Con) Engineering the upward hinging is more difficult, and hinges will likely be very visible on the finished layout.

    Con) Structure clearances near the joint must be watched on both the folding and fixed sections. Mounting the hinges on small blocks on high points on the fixed section or using offset hinges will help but not eliminate this factor.

    Con) Supporting the folded section in the up position is more difficult. Easiest answers are a ceiling tie, or ties to either side of the fixed section, but neither has the leverage to raise the folding section at certain parts of the swing arc. Since the folded section is fairly small, manually lifting it should be acceptable.

    Con) Light weight, very rigid construction is required. Probably the framed foam "dominoe" construction would suffice.

    As you can see, I like to steal ideas shamelessly, and then add on. ;)
  10. babydot94513

    babydot94513 Member in training

    Not that I am contemplating using this concept, your observations make complete sense to me and words to consider if going down this path.

  11. Russ Bellinis

    Russ Bellinis Active Member

    Atlas now offers packages of snap track in 1" or 2" lengths, perfect for "joiner tracks" for a folding layout. The other thing you could do is to use a piece of cork roadbed ballasted with ties, and short sections of rail that would join the fixed track at each end. They would rest on the ties and be held in place by rail joiners to the fixed track at each end. The rail sections should be as short as possible, but minimum length is probably the length of two rail joiners end to end.
  12. shortliner

    shortliner Member

    Elwood - email me direct - I have a couple of trackplans that fit your requirements - but "squishing" them to fit on here ,makes them unreadable
    Shortliner(Jack)away up here in the Highlands
    chacmool at lineone dot net

Share This Page