Con-Cor 2-10-2 Question

[mike_lawyer]

I am doing some research with regard to potentially having some locomotive frames fabricated to fit Kato Mikado parts to create a USRA heavy 2-10-2 design.  I have not owned a Con-Cor 2-10-2, so my question is this - on the Con-Cor, is the main drive rod only connected to the first and third driver (like on the Kato Mikado), or is it also connected to the 5th driver?  Thanks.

[reinhardtjh]

Mike,

  Drivers 1-4 are connected to the drive rod.  The 5th is floating.  If it makes a difference, drivers 2,3,4 are connected to one rod and then there is a short rod from driver 2 to driver 1.

[Maletrain]

Mechanically, starting from the front, diver 1 is not gear-driven, but is connected to the gear-driven drivers by a short connecting rod.  Drivers 2,3, 4 and 5 are gear-driven and a connecting rod also connects drivers 2,3 and 4 and extends to look like it connects to driver 5, but does not.  If I remember correctly, drive 5 has a traction tire, which would be easy to replace because there is no pin connecting the rod to the wheel.

[mmagliaro]

My Con-Cor 2-10-2, which I am looking at in the box, is as follows:

1. Numbering the drivers 1-5 from front to back (#1 is at the front of the engine)

2. Siderod is pinned to 1,2,3,4.  It is not pinned to #5.

3. Drivers 1 and 2 are not geared.  They are pushed around by the rods only.

4. Drivers 3,4,5 are geared.

5. Traction tire on #5, which is the floating, un-pinned driver.

[mike_lawyer]

Thanks everyone for the info, interesting that they designed it with the siderods pinned to the first four drivers, when the Kato Mikado just has drivers 1 and 3 pinned.  The Kato design seems more bulletproof from a quartering and valve gear perspective.

[mmagliaro]

With a 5-coupled engine, and its longer rods, I think that pinning the rod on only 2 drivers would have made it visually look a little out of sync with the positions of the counterweights.  Given the tolerances on the gears and the necessary slop in a typical mechanism, even a good one, I think the rod would sometimes look like it was flopping around in front of the unpinned drivers.

I think I would have made drivers 1 and 5 *both* be non-geared, instead of 1 and 2, allowing the two extreme ends to have maximum lateral play for negotiating curves.  The center driver is blind, something I neglected to mention, so you really want the outermost drivers to be able to slide left and right.  If 2,3,4 were geared, with the traction tire on #4, then the rod could be pinned to 1,3,5.  That would get rid of all the disassembly/reassembly quartering issues.  You drop them all in, and 1,3,5 would HAVE to be correctly quartered, just like on the Kato, because that's the only way the rod holes would line up.  2 and 4 are only geared, so you just drop them in so the counterweights look right, but they won't affect quartering, even if you are off a tooth on the gear.

By putting the two un-geared drivers up front, the lateral play on #1 is very wide, which is one of the reasons the wheel back nubs can slide out of the bearings and jam up the engine when it comes out of a curve, unless you do some shimming to restrict the lateral play, and not let the engine run on as tight a radius.  A few washers on the front axle to limit that play keeps this problem in check, at the expense of a broader minimum running radius.