Dual Cross overs??

Discussion in 'Track Planning' started by zigg72md, Jun 21, 2006.

  1. zigg72md

    zigg72md New Member

    I hope this is the right place to ask. If not where?

    Does anyone know where I can get information on how to get or build a O-27/On30 crossover? I am trying to create a dual gauge layout and need to cross the On30 (ie HO) gauge track over a O-27 loop. Or am I just dreaming?
  2. pgandw

    pgandw Active Member

    If you need to cross at the same level, you will have to "scratch build" one. Not as hard as it seems, but a couple of helpful hints:

    - transition the O27 track to Atlas 3 rail O near the crossing. The Atlas track uses solid rail similar to HO track.

    - use the Atlas O track rail for both the O27 and the On30. Buy the rail separate or strip from some track.

    - use wood ties and spikes would probably be the easiest

    - You do not have to have a continous middle rail for the O27. Stop the middle rail just short of the On30 rails, and add a short segment in the middle of the diamond. Make sure there are either short vertical ramps or constant height structures where middle rail pickups and sliding shoes will pass over the crossing.

    - my biggest concern as far as practicality would be the width of the flange ways for the O27 wheels - they might be large enough to cause a serious drop by the HO size wheels crossing them.

    Much, much easier if you can possibly find the space is to have one gauge pass over the other on a bridge. Even a steep 5-6% grade would be easier to build and less likely to have derailment problems.

    yours in tracking
  3. Russ Bellinis

    Russ Bellinis Active Member

    Good point about the size of the gap to clear O-27 flanges causing derailing problems for the On30 wheels, Fred. I'm just kind of thinking as I type here. I don't know how wide the flanges are for O-27; and if the flangeways aren't wide enough, the O-27 wheels could short out the ho track used for On30. I'm wondering if it would work to use a bit of plastic kind of extend the ho rail and tighten the flangeway for the O-27? It might be that the plastic would keep the gap from being too big, and still keep the O-27 wheels from causing short circuits on the ho track. Isn't Atlas 3 rail O gauge made with code 125 rail? If so, he would need to shim up the ho track (code 100) so the railtops would be level on the 2 gauges I think. Another method I just thought of as I posted would be to cut the ho tracks about 1/4 inch short at the crossover and about 1/2 inch short in the diamond. Use Atlas insulated rail joiners on the ends of the rails and on each end of the tracks in the diamond, and put in a piece of rail on the end of the insulated joiner to come just flush to the end of the joiner. If it is put together with epoxy to hold the joiner and rail together, the small pieces won't fall out. You then make sure to leave the short bits at the ends of the insulators electrically dead.
  4. pgandw

    pgandw Active Member

    Atlas O track, I'm told in another forum, uses code 215 rail. My quick check with a ruler (not calipers or micrometer) said around 1/4" or code 250, so I'm willing to believe code 215 (double the rail height of HO code 100 track).

    The prototype normally built turnouts and crossings with heavier rail than the lighter track used, usually the same as, but sometimes heavier than the heavier use track. So it would be appropriate to transition the On30 (HO gauge) track to the code 215 before getting to the crossing. That would take a couple of inches to transition that 1/10+" difference in rail height.

    Thinking about the problem some more - wiring the bugger would take a little planning. If you allow the O27 center rail to be discontinuous and insulated from the rest of the rail in the crossing, you would only have to have gaps in the 2 outside O27 rails between the 2 frogs. All the rest could be continuous metal rail and frogs, as far as the On30 is concerned. However, there would be short circuits when O27 center rail rollers were touching both the crossing On30 rail and the live center rail at the same time. So the On30 rails would have to have a short isolated section where the O27 center rail would be. Then insulate the whole crossing from the rest of the track and use a DPDT to select whether the crossing would be set for O27 or On30. When set for On30, all the On30 track segments would be live, and the O27 center rail would be dead. When set for O27, the center rail segments and On30 center segments would be live, and the rest of the rails would be connected to the O27 outer rail.

    After sorting through the wiring issues, I realized that the center O27 rail can be soldered to the isolated center section of the On30 rail with just one gap at the center of the crossing, since it will be switched as a unit. This would give an H configuration of metal rail down the center of the O27 path. As long as the top surface is kept smooth, should work like a champ.

    My stuff is in storage while I'm doing a drawn out move so I don't know how wide an O27 flangeway has to be. Except for that worry, it would be a fairly simple exercise in handlaid track construction as long as you are willing to use soldered frogs and add all the gaps and feeders needed for the above wiring scheme.

    Still, I would think an over/under bridge crossing would be more reliable and fun if the room can be found for the grade - rail to rail clearance would have to be about 5.5" for the On30 to go over the O27; maybe an inch less for the other way around?

    An interesting planning exercise no matter which path is chosen. I had done a feasibility check for the minimum size for an O27/On30 layout that featured a narrow gauge to standard gauge transfer facility as its focal point. It fit into a 5ft x 8ft space with an O36 oval with passing siding and 3 spurs, one of which served the transfer platform. The On30 used 18" radius on a small point to point (half oval) from the transfer platform to a town at the top of a grade.

    I think the mixture of O27 and On30 would be a lot of fun, as long as you are not taking prototype modeling too seriously. Most O27 and On30 users don't because of the obvious discrepancies in their track, so it shouldn't be an issue. Now that I've done so much planning of the crossing, I'm going to have to build one for kicks when I finally get relocated!

  5. 60103

    60103 Pooh Bah

    I just ran the calipers over a couple of Lionel cars. The recent car was tighter gauge (and fixed to the axle) at a bit under 1 1/16" back to back. That makes 2 x 3/32" gaps. Not sure what this means for HO wheels, but it seems large.
    The wiring would prabably require at least a DPDT switch, maybe something more extreme. You'll have two different power supplies and 6 segments of track (but really only 4 bits that need separate wiring.
  6. zigg72md

    zigg72md New Member

    I think I will take the advice to use an elevated crossover instead. Thank you everyone for your help.

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