First 3-Rail to 2-Rail Conversion!

A suggestion.    Obtain a Kadee Coupler gage and use it to set the coupler height.     Most 2 rail cars are built to NMRA recommended standards which is what the gage will measure.      that way if  buy more cars already 2 rail, you won't have to adjust coupler heights.

Thanks for the suggestion! I do have a Kadee height gauge and that car is the proper height. I was gonna show the height gauge but figured the car would look better. 

Here’s something that’s always bugged me. Why aren’t all non powered trucks 2 rail? Then all scale modelers could buy 1 type of rolling stock and just have to decide on the couplers. What am I missing?

OK, since you didn't mention it, I was not sure  you were aware.    For Scale modelers, the NMRA has recommended practices and standards for most scales and that includes height of underside from the rail and coupler height.      Most mfg that cater to 2 rail O scale (and of course HO) follow these recommendations.      for the most part the 3 rail mfg ignore them, so you often have to adjust heights and what not when converting.    Part of it the need for higher truck clearances for the big couplers, and I think part of it that their business plans tell them to make their incompatible with other mfgs to make it more convenient to only use their brand.     In 2 Rail most mfg are smaller and do not make all products needed under one brand, so they use NMRA standards to try keep things compatible and convenient.

I think you can access the standards on the NMRA website without being a member.

prrjim posted:

OK, since you didn't mention it, I was not sure  you were aware.    For Scale modelers, the NMRA has recommended practices and standards for most scales and that includes height of underside from the rail and coupler height.      Most mfg that cater to 2 rail O scale (and of course HO) follow these recommendations.      for the most part the 3 rail mfg ignore them, so you often have to adjust heights and what not when converting.    Part of it the need for higher truck clearances for the big couplers, and I think part of it that their business plans tell them to make their incompatible with other mfgs to make it more convenient to only use their brand.     In 2 Rail most mfg are smaller and do not make all products needed under one brand, so they use NMRA standards to try keep things compatible and convenient.

I think you can access the standards on the NMRA website without being a member.

 

It’s like you read my mind! Asked and answered simultaneously!

prrjim posted:

OK, since you didn't mention it, I was not sure  you were aware.    For Scale modelers, the NMRA has recommended practices and standards for most scales and that includes height of underside from the rail and coupler height.      Most mfg that cater to 2 rail O scale (and of course HO) follow these recommendations.      for the most part the 3 rail mfg ignore them, so you often have to adjust heights and what not when converting.    Part of it the need for higher truck clearances for the big couplers, and I think part of it that their business plans tell them to make their incompatible with other mfgs to make it more convenient to only use their brand.     In 2 Rail most mfg are smaller and do not make all products needed under one brand, so they use NMRA standards to try keep things compatible and convenient.

I think you can access the standards on the NMRA website without being a member.

 

Gotcha! The reason why the kadee gauge wasn’t preferable is because the ends of the car go slightly beyond the sheet metal of the bottom of the car. The 2 rail model, like the cabooses, have a specially soldered metal pad to mount the couplers on. I called Sunset 3rd Rail and they didn’t have any spare parts. 

If I didn’t have the other model to height match, I would have built the coupler mounts first and then adjusted the height based on the Kadee gauge. I would have referred to prototype photos to get the mounting pad height as close to the prototype location as possible. I haven’t had to do that yet, but other modelers have recommended that’s what I do if I need to. 

prrjim posted:

I think you can access the standards on the NMRA website without being a member.

 

You can.

Marty R posted:

Here’s something that’s always bugged me. Why aren’t all non powered trucks 2 rail? Then all scale modelers could buy 1 type of rolling stock and just have to decide on the couplers. What am I missing?

Another reason all non-powered trucks aren't 2-rail is that they usually derail running through 3-rail switches.   The frogs, flange guards and other parts of most 3-rail switches are too wide for most 2-rail equipment.  2-rail wheels tend to fall off the track when going through 3-rail switches because the clearances are too coarse.   Also, most 3-rail switches are too sharp for the swing of 2-rail trucks.  The underbody detail on 2-rail freight and passenger cars tends to limit the truck swing to wider curves than are found on most 3-rail layouts.   It is easier to convert from 3-rail to 2-rail than in the other direction.  NH Joe

Marty R posted:

Here’s something that’s always bugged me. Why aren’t all non powered trucks 2 rail? Then all scale modelers could buy 1 type of rolling stock and just have to decide on the couplers. What am I missing?

First, welcome to the world of conversion therapy. I've found that I'm happier with Kadees and scale wheels on equipment, though I do get the occasional piece of uncooperative equipment when running at the club. I'm converting equipment as I have time and materials. If you're living in both worlds as I am, a few reliable "transition cars" will help.

Modernly, it's more of a legacy thing. You have to go back decades when there were "toy" trains and "model" trains. Toy trains ran on tubular track with extremely sharp curves of as little as 13" radius (O-27) and inside-third rail for layout flexibility (no reverse loop issues). To accomplish this, truck-mounted couplers, wider treads and larger flanges were required to prevent derailments. Modernly, scale equipment built to run on 3-rail legacy track systems were set up with the same wheel set design, though they did require larger curves in many cases. Turnouts were designed around this flange/tread setup and though there are NMRA-similar turnouts for 3-rail they maintain the frog/guard rail configuration to support the legacy wheel set configuration, so 2-rail equipment has some issues on #6 and larger, plus curved-frog turnouts due to the spread and gap in the frog. We compensated for this at AGHR by putting a moving point in a #8 curved turnout.

Early model trains were more in line with modern 2-rail design, but ran using outside-third-rail. This evolved into 2-rail as wheel/axle insulation methods improved (it is my contention that had a viable sectional outside-third-rail been developed we'd all be 2-rail by now). Early 2-rail wheel sets had a larger tread (code 172), but the back spacing between the flanges was/is still compatible with modern track systems. As these were models, couplers were more in line with scale size and body-mounting became the norm since broader curves were in use. Equalized trucks that floated with the track compensated for bad spots in the track where the rails weren't quite even.