Converting a RTR car to Proto:48

It has been far too long since my last post - over six months in fact. Not to say that there hasn't been progress on the layout.

Most of my time spent on the project since the last post has focused on layout design. One big roadblock has been trying to figure out a minimum curve radius for the track plan (post coming soon). 

This led me to a second project: converting a few freight cars in order to test different curve radii. 

Assembling what I need to lay some track and test the operating limits of proto:48 couplers took most of the summer. The poor Canadian dollar meant that I had to save up hobby funds a little longer than usual, but eventually I was able to put in an order with Protocraft for couplers and wheels, and Right-O-Way for track components, including proto:48 track gauges and switch parts.

The first car I pulled off the shelf was an Intermountain PFE steel reefer. It came assembled, so I set about removing the IM trucks and Kadee couplers. 

The first victim waits on the workbench. 

Next was adding the scale, operating couplers from Protocraft. These are exquisite, and function just like the real thing using either the lift bar or a magnet to open the coupler. They also come fully assembled - thank goodness! 

Protocraft's Symington-Gould Type-E brass working coupler and draft gear assembly. Image from Protocraft's website.

The hole for mounting the draft gear was a bit off from the one on the Intermountain under frame, so I had to plug the existing holes with styrene rod and drill new ones. I also had to trim some of the end of the frame on the IM kit to make room for the new draft gear (see image above). 

Protocraft supplies scale draft gear box with the couplers (unlike the oversize/overwidth Kadee-style boxes we are all familiar with). Unlike the couplers though, you need to assemble the draft gear. The instructions for the draft gear assembly took a little work to interpret, and getting the box, cover, coupler and spring together in one piece long enough to attach to the underframe might require a trick I haven't figured out yet - like tacking it all together with a bit of glue.

I'd also prefer that the box used a flat-head screw (as opposed to the supplied pan head) with a countersunk hole in the draft gear body. This would hide the screw better and improve the overall appearance. It is a modification I will look into later. 

Success! The first coupler mounted. 

The wheels were much easier to convert. I ordered Protocraft's 50-ton, single insulated wheelsets to use in the stock Intermountain side frames. The side frames are a bit crude and too wide (a byproduct of standard O scale track scaling out a bit wider gauge than the prototypical 4' 8.5"). I decided however that they will have to suffice until I can upgrade the modest fleet of rolling stock at a later date. 

Standard O-scale metal wheels at right, and scale, proto:48 gauge Protocraft wheel below to the left.

I selected the IM wheels based on this blog post by fellow P:48 modeller George Losse. The Protocraft axles were not designed to be a great fit in the IM side frames, but they roll. I will try to shape the axle ends a bit to get them to roll better as George recommends in his post. 

Otherwise, the trucks were a breeze. Together with the scale couplers, they really make a difference in appearance - even on an out-of-the-box model like this one. 

With two of these cars upgraded and track gauges in hand, I can now test the tolerances of the Protocraft couplers to determine what the minimum radius on the layout can be.

Perhaps one of these days I'll be able to get around to actually starting the layout!