Building the Turntable Pit

The EBT roundhouse and its turntable form a single unit.  Access to and from the roundhouse passes over the 65 foot steel girder turntable.  Some evidence suggests that the EBT purchased the bridge of the turntable from the New York Central Railroad.  A duplicate turntable serves the roundhouse of the Durango and Silverton Railroad in Colorado.

Whatever its history, the turntable has to be installed in the foam base at precisely 70 feet from the front wall of the roundhouse, and the eight tracks of the roundhouse must all line up with the center of the turntable.  I opted to purchase a laser cut kit for the turntable made by Kitwood Hill Models in the U.K.  The price, at slightly over $100 U.S., was certainly reasonable for a powered HOn3 table.  (The model is not indexed and must be lined up by eyeball, just like the prototype.)

I received a box of parts from Simon Cox, who owns Kitwood Hill Models, including laser cut parts for the pit and the bridge, and a separate bag for the motor and gear pack parts.  Also included were detailed instructions for assembly.  Be sure to read the instructions carefully and follow them exactly.  I failed to to this and found myself going back and redoing some of the work.

Many of the laser cut parts must be carefully removed from their carriers.  Usually there are a few small tabs that connect to parts to the carrier.  Use a hobby knife to cut the tabs and gently remove the parts.  Simon also gives good advice about glue (avoid water based glues so as not to warp the wood) and soldering.  The pit rail must be soldered to PC ties, as explained below.

Assembly begins by gluing a stiffener ring to the base plate.  Simon recommends using contact cement for large parts, and I found this to work well.  Smaller parts were glued in place with ACC.  The kit includes small "axles" that go through the parts being cemented to make sure they are properly aligned.

The first major step in building the pit is to construct the base for the running rail that encircles the pit and in the prototype supports the weight of the bridge.  A ring is provided marked with the locations for the 24 PC board ties to which the code 75 rail will be soldered.  The PC ties are glued to the base with ACC.  I glued two pieces of 1/16 inch square basswood into a simple jig to position the ties.

Once the PC ties were in place, wooden ties were glued between them using ACC.  The same jig was used to position the ties vis-a-vis the inner edge of the support ring.

The kit includes a length of code 75 nickle silver unweathered rail for the pit rail.  The rail is formed around a jig made from four pieces of laser board that assemble into a circle.  One of the PC ties is wider than the others, so that the ends of the rail can be soldered to it, as shown below.  Note the metal axles that properly position the jig to the base.

Once the rails are soldered to the PC ties looks like this:

The running rail support is then glued to the pit base.  Note the holes in the base, which will guide the installation of the gear box and motor.  At this point, Simon Cox recommends painting the ties, rail and pit base, as shown below.

The sides of the pit are made by attaching the pit base to the top ring, which supports the pit once it is installed on the layout.  In the preceding photo I have placed the top ring on the pit base.  The top ring rests on 24 laser cut uprights that are glued in place with ACC.

A word of warning.  It is critically important that these wooden uprights be fully inserted in the pre-cut holes in the top ring and the base.  Otherwise the pit will not be level and you will have all sorts of problems when you install the bridge.  I made this mistake, and as you will see.

In the above photo you can see how the pit base is attached to the top ring.  If you look carefully, you may be able to see that some of the wooden pegs that hold the two assemblies together are not fully inserted in the top ring.  Ooops.

Before I realized the problem, I followed the next step in the instructions, and installed the pit walls, which are made from four strips of 1/32 inch plywood.  The strips have to be gently formed into a curve to fit inside the pit against the uprights, and glued in place with ACC.  Be careful!  They break easily.  I know from experience.

It was about this point when I realized that the top ring of the pit was not level.  I turned the pit upside down on a sheet of glass and found that I could rock it back and forth by a good 1/16 inch!  I realized the error, but by then all the supports had been glued in with ACC and the entire assembly was solid as a rock!

The solution I came up with wasn't elegant, but it worked.  I found that the correct distance between the pit base and the top ring should be 1/2 inch when the uprights were fully inserted in their holes. But some of the uprights were not in all the way, making the height off by as much as 1/16 inch.  The only workable solution was to cut one end of the overly long supports with a Dremel tool, insert a 1/2 long inch piece of square basswood next to the original upright, clamp and glue it tightly to the original support post and the the top ring.  It may not be elegant, but the results were worth the effort.  Here is what the corrected pit looks like from the side.  Now the pit assembly rests flat on the sheet of glass, and there is no visible rocking or warping.  Whew!

At this point Simon recommends painting and detailing the kit.  I painted the ties with Floquil roof brown and the rail with rail brown.  The floor of the pit was painted a light brown.  It will eventually be covered with grass, weeds and gravel.  The sides of the pit were painted with Floquil aged concrete.  The holes in the top ring and the cracks between the pieces of plywood were filled with spackle and then painted.

In the next installment, I will detail the construction of the turntable bridge, the gear box and the motor that operates it.