John,
I have really enjoyed your and your wife's articles and videos of the Glacier Lines. It is the type of layout that I would build if I had the space.
There are several 2-rail shows scheduled for 2021. The one nearest you is probably the Chicago March meet. I have never been to this show but I have attended O Scale West many times. If the March meet is anything like O Scale West, there will be tables full of very nice 2ROS rolling stock at clearance prices. I am talking about box cars at $1O each, etc. Buying used 2-rail equipment could cost less than buying new wheel sets to convert your 3-rail equipment.
The biggest issue with running 3-rail equipment on 2-rail track is that the 3-rail wheels and axels are not insulated. This means that standard 3-rail equipment will always short out when placed on powered 2-rail track. It has nothing to do with track polarity. You must change the wheels to avoid this. Also, you usually need to modify the 3-rail car height so that it will match with 2-rail Kadee couplers NMRA standard height. I can't see staying with claw couplers if you are making everything else scale.
I have several MTH PS-3 2-rail engines that run fine on 2-rail track using DCC for command control. (I bought the 2-rail version. As you probably know, MTH has a kit to convert 3 rail to 2 rail for their 3/2 diesels.) These engines in the 2-rail version come with insulated wheels. I also have two MTH PS-2 2-rail steam engines that I had converted to PS-3 so I could use the DCC feature that comes with PS-3. This eliminates the polarity issues that comes with the PS-2 3/2 engines. I would think that if you are going scale that you will want to use DCC on your modular layout.
You might want to check out Rich Batista's Black Diamond Lines videos. He describes how he converted 3-rail to 2-rail in one video. Another source is O Scale Resource magazine. This magazine is only online line and it only deals with 2-rail. The current issue has a very good article on converting a MTH car from 3 to 2-rail. Another source for information is the O Scale Kings organization.
Thanks again for sharing the Glacier Lines with the model railroad community.
I hope that this helps. NH Joe
