Sunday, August 1, 2010

Tight radius stress

After a recent discussion on the Yahoo N scale traction group about minimum radius curves for N scale trams, I thought it would be a good idea to make a list of trams which make it through a 103mm radius (the tightest commercially available) and which ones won't. Test location was my little layout-to-be. It turns out that all trams make it through really, but the Bachmann PCC and Arnold Düwag are quite noisy, which indicates stress on the gears. Definately not healthy in the long run. And especially the Arnold is a little too expensive to ruin this way...

No problems with 103mm radius:
Kato 'pocket line' tram chassis
Kato 'shorty' 4 axle chassis
Tomytec LRV chassis (Portram, Centram etc.)
Bachmann Brill trolley

Noisy on 103 mm radius:
Bachmann PCC
Arnold Düwag (and a little smelly as well...)

This really makes me think about using 140mm as a minimum for future layouts.


  1. Add to your list of "works but maybe not 100% happy" the really small Tomix two-truck mechanisms (TM-01/TM-03).

    I have two cars powered by these--one works fine, but the other slips and has trouble getting going on the curves. Not sure where exactly the slipping is happening.

    But when I set up some 140mm curve track (for running Thomas with my kid!) even the "slippery" mechanism worked fine.

    To the "runs on 103mm but noisy" list add the Modemo articulated cars (NT60 and others).


  2. One more thing to consider--for long articulated cars, the average curve radius may be the key.

    Somebody on the NScaleTraction or the Tomix list said they put straight sections to space out 103mm curve sections, and long cars were ok with them.

    Real railways usually ease into curves. This is much easier on cars and passengers. If you were riding a streetcar that went into a sudden, constant-radius curve like our 103mm-based layouts, you'd feel a lurch to one side (there's a ride a local amusement park that does this!).

    So combining radii might be both realistic and produce better operation.

  3. Thanks for your additions Nick! I like the idea of combining radii, especially when it helps more models through the curve. Still, I think I'll go for a minimum of 140mm in the future, just to be shure...
    By the way, I noticed on your blog you have an Arnold Düwag as well, does yours make noise as well in tight curves? Mine was purchased second hand, so it might be just my particular one.