Test Track Project


Test Track Construction

In October 2003, development of the test track began with construction of a plywood base on which the layout could be mounted. The base was actually a box with a drawer for the layout's electronics.

By successfully applying the “measure twice, cut once” principle of woodworking, I managed to create the necessary parts for the base from a 2‘ x 4‘ x ¼" piece of plywood, a 6‘ length of 1 x 3, a 6‘ length of 1 x 6, a heavy-duty 22" drawer slide, and assorted screws.

Parts Kit

The assembled structure provided a 15" x 30" base for the layout and an 11" x 23" drawer to hold the electronics. To allow easy access to both the layout’s underside and its electronics, the drawer was mounted on full extension ball bearing slides.

Most of the wooden parts were painted with white primer; however, the surface on which the track would be mounted was painted with gray primer. Gray was chosen, because it closely matched the color of track ballast.

Completed Box

The plastic front on the drawer was not part of the original design; however, it was added when I realized that our small cat would try to crawl inside the drawer if given the opportunity. Small furry animals, low humidity, and sensitive electronics do not mix well.

Track Plan—First Attempt

By the end of 2003, track had been laid and some basic testing was underway. As seen in the photo below, the track plan had reversing loops and very sharp curves (4.5-inch radius). It was soon discovered that the curves were too sharp for reliable operation, and the reversing loops only served to make a bad situation much worse.

Track Layout—First Attempt

After much procrastination (almost a year), I finally ripped up the track, installed a slightly wider plywood base, and simplified the layout.

Revised Track Plan

The track plan for the revised test track consisted of two concentric loops of track (no reversing loops) as shown in the diagram below. This is the same layout that was used for Coffee Table #1. Minimum track radius for the new test track was 6.5 inches.

Test Track Layout

In the drawing, section breaks are shown as short red lines. For easy reference, sections are numbered, turnouts are lettered, and magnetic reed-switch sensors are labeled as "RS".

Note: Although the layout included magnetic reed switches for sensing train location, early experiments proved that current sensors would be more reliable and would provide better train location information. In addition, the current sensors would provide train direction (eastbound, westbound) information. The magnetic reed switches were eventually disconnected.

Track Layout—Second Attempt

As noted above, the new trackage had a minimum radius of 6.5 inches, which resolved the reliability problems—almost. The relatively sharp curves made it necessary to modify several of the engines.

Engine Modifications

As the train attempted to negotiate the test track's sharp curves, sideways movement of the engine's truck-mounted coupler was restricted by the width of the opening in the end of the engine's plastic cover. This restriction forced the front coupler of the attached car to the side, thus derailing the car's front truck.

The solution to the problem was to widen the opening in the engine's plastic cover, as shown in the photo below. The engine on the left has not been modified, while the engine on the right has been modified.

Engine Modifications

Note: Engines that have their couplers mounted on the the engine shell, rather than the truck, do not have this problem, and no modifications are necessary.

None of the passenger cars or freight cars used on the test track needed modification. However, in the original coffee table (Coffee Table #1), all of the rolling stock—engines and cars—required modification.

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