Matching similarly performing engines

[cruikshank]

Last post for the night.  Couldn't sleep lots of questions.  Again same club layout, running three trains on one mainline with stops track, trigger tracks, and passing tracks.  Units get out of sync when one engine/train runs much faster or slower than the others at the same voltage, say 9.5 VAC.  Now some appear to be cheaper set engines, some are much better grade engines, and I gues some are older AC vs newer DC with Flywheels.  Is the best way to set up a test track with a volt and amp meter, and test the starting voltage, current draw etc of each, in order to find similar performing engines?  For example we had an MTH Blue Goose and an MTH PRR K4 they both pulled and ran pretty similarly.  Then we through in an older heavy GG1 by Lionel.  Drew much more current, and took much higher voltage to get up and go from a dead stop.  These older Lionel F3's could only pull about 6 cars, while a T-1 will pull 25.  What's the best way to go about this.  All are being run on conventional control.   Thanks again.  Dave

[dsmith]

I use stop control blocks on my conventional small layout and have the same problem with faster trains overunning the slower ones.  I have minimized the problem in two ways.

1.  The faster engines get more cars to pull (or the slower get less).  This slows them down a little.  Also the faster engine gets the heavier cars (or the slower gets the lighter cars).

2.  I reduce the voltage to the faster engines in the following way.  Using a pair of opposite facing 3 amp diodes in parallel wired in a series with the motor allows you to reduce the voltage of the faster engine by about 1/2 volt.  If the engine still is too fast, then add a second or third pair of diodes.  Diodes work great becuse they reduce the voltage by a precise amount that does not vary with load.  If you need a diagram, let me know and I'll draw one up and post it.

[lionelsoni]

What David suggests can also be done with bridge-rectifier modules, which provide you with 4 diodes in a single package.