Tuesday, November 8, 2022

Stanstead - A Custom Turntable - A Follow Up

Stanstead may be seen as a race, or a marathon… but at least some experiment with a deadline and a need to move forward instead of getting bogged down. As a module, it is nothing more than a general rehearsal before delving more into Monk Subdivision later. The time limit is somewhat artificial but is basically tied to Christmas and having time to figure out the electronics that will be the brain of Monk.


One of the big challenges has been to build a suitable turntable. This is something that was on the back of my head for years but which I never dared to do. I was convinced I would use the tried-and-true Bob Hayden’s method with the phone jack plug once explained in a Model Railroader article many years ago and previously shown in a post written a few days ago.


I decided early on the turntable would be 9 inches long to fit most of my locomotives which translates roughly to 65 scale feet. I felt it was a quite prototypical length for a branchline turntable built in the late 1800s. A quick search online shown me the old CPR St. Mary’s pitless steel turntable would be a perfect fit for the project. I had only one goal, make the turntable as mundane, small and subdued as possible. I didn’t want it to be the center of attention, but merely a supporting character. Having had the joy to operate once on Trevor Marshall’s Port Rowan layout, I knew they simpler these elements are, the better they blend into a compelling scene.


As for designing the turntable, I decided to build it on the go, not bogging me down trying to figure out each detail (analysis paralysis isn’t it!). I started with a decent understanding of what I was doing then elected to go forward quickly and troubleshoot issues has they would arise during the building process.

Last time I wrote about the turntable, it was painted and ready to be installed. I thought some more info on the painting process could be shared.

The girders were primed dark brown, then with a sponge, I added lots of colors including light blue, orange, red oxide and purple. When you look at a read rusted girder bridge, you can see a lot of color variation going far beyond earth and rust colors. When dry, I applied 2 coats of hairspray and a light coat of weathered black (mainly black with white, blue and green mixed in it). After an hour, using an old brush with water, I started to dab the black paint to create chipping effects. I didn’t go overboard as I wanted a weathering level adequate for a 20 years old steel structure that wasn’t repainted since installation. After that, I drybrushed the rivets with a light color to make them pop, applied a few washes and some rust weathering powder on top of the lower and top chords. Classic stuff if you ask me. Later, I’ll add wooden handle as per prototype since it’s an Armstrong type turntable.


Fitting the turntable to the layout was more complicated than anticipated. I removed all the scenic materials, including fiberboard and cork until I reached the original plywood board. As this is a recycled baseboard, several layers had been added over the years. A 1/2” plywood plank was cut to size and a hole drilled to host the female part of the jack plug. Once again, that part was mounted on a 2.5 styrene sheet secured on the plywood with screws. Unfortunately, the turntable bridge was too high and I had to carve a niche into the plywood with a chisel to sink the styrene mounting plate.

The pit rail on glued on the MDF ring

 At first, I wasn’t sure I wanted a pit rail but it became obvious it was prototypical and that I needed it to make sure the bridge was perfectly aligned. The jack plug can induce some wobble than must be countered. The pit rail was mounted on a ¼ MDF ring that I sealed with carpenter glue. A strip of cardboard was temporarily glued on the outside and would be used as a guide to install the rail and make sure it was perfectly circle. I used Atlas code 55 rails slided into Peco code 83 ties cut in half. Before gluing, I carefully curved the rail by hand to give it the correct curvature. You don’t want tension forces in your rails when the radius is about 4.25”. The pit rail joint was soldered and the assembly was cemented with 5-minutes epoxy glue. When dry, the MDF ring was then glued and screwed into place. Why screws? MDF is notoriously knowns for warping, thus adding 8 screws and glue made sure it wouldn’t bulge in the future.

Finally, pit assembly was permanently fastened on the layout board with screws in the right alignment and the approach track was laid in place. Old grey leftover timbers from a very old wooden bridge project were used, cut to length and assembled to create a retaining wall at the end of the approach track as was usual for turntable that didn’t have a concrete or stone walled pit.


On prototype, the spacing between the rail is minimal

The last step will be to add brass bearings (probably brass tubing) under each end of the turntable. These will slide on the pit rail and ensure the bridge is always perfectly aligned and horizontal. The girders are about 1.5mm over the rail head. 

1 comment:

  1. Matthieu, where did you get those beautiful Girders for the Turntable? I'm doing CP Rail Goderich and have been putting it off on account of the Turntable. This article might give me the push I need to get this thing done! Thanks