Sunday, April 2, 2017

Streetcar test track and the search for a happy minimum

I was reading on wikipedia that the TTC streetcar system has a minimum turn radius of 36', which translates into about a 5" radius curve in HO scale. My previous layout had minimum 15" radius curves; far too large for a convincing representation of the street. I laid down a lumpy loop of track - almost an oval at one end - of 5" radius to run some tests with my fleet.
It turned out only one end was more-or-less circular and the other was a bit too oval, but it worked out to be a fairly ok 5" radius test track. Only the Bachmann Birney single truck tram could handle that tight curve. None of the PCCs could.
I was crazy when I built that loop. I figured on all members of the fleet successfully negotiating the 5" radius curve. I got a little smarter when I had to do tests with 6" and 7" radius turns. I drew a guide on my cork board and temporarily thumbtacked down a strip of track. It turned out to be a good approach: a 6" radius curve was also too tight, but 7" worked just fine. To be a little more specific: the Bachmann Peter Witt could handle a 6" radius curve, but the Bowser and Con-Cor PCCs couldn't, although they could handle a 7" radius turn. It looks like 7" will be the minimum radius for curves on the new layout.


  1. This is useful, helpful stuff. What sort of flex track are you using? I know Atlas has really easy-to-flex track, but other brands do not flex as easily without coaxing (and sometimes swearing).

    1. Thanks! I used Atlas flex track for both this HO scale test setup and the N-scale one I posted about earlier. But, for the N-scale EVRR layout I'm planning to use Peco. I like their switches and I've bought the ones I need. I've also got a few lengths of Peco flex. It seems a little stiffer than the Atlas, but I haven't worked with it enough to know for sure.