HO Scale Modules

Local Loco HO Club Modules

This document was created to document the specifications for the existing HO Club modules.

Currently (April 2020) about 16 modules exist.  These include 4 corner modules, 6 straight 4’ modules, 4 straight 6’ and 2 straight 2’.  The straight modules vary from 24” to 30” deep (front to back).  The corner modules are cut from a 4’ by 4’ square with the front (public) and back 2’ by 2’ triangles cut off so that a 2’ angled surface remains on the back portion to join with the straight modules.  The result is a 6 sided unit about 34” front to back and about 68” along the long diagonal.

Most modules are built with 1×4 sides and a 1/2” plywood or similar surface.  Best results include at least 1×2 supports on 16” centers under the plywood.  Removable 2×2 legs have a 3” x ¼” or 5/16”carriage bolt screwed into a T-nut in the bottom so that the surface of the modules is 30” above the floor (child’s eyeball height!).  Some modules have attached folding legs with adjusting screws.  During setup, the height of each module is adjusted to make the rail heads of adjoining modules match.  This allows for variations in the floor of the display area.

Many modules also have a backdrop of luan plywood or 1/4” Masonite about 18” high across the back and the back half of the sides.  The 18” is measured from the bottom of the frame, or 14” above the plywood surface of the module.  We also added a 1×2 or 1×4 frame to support the top edge of the back and make a support for the optional sides.  The sides have a “Tunnel Portal” hole cut through for the third track, from the roadbed to 4” above the railhead and 2 1/2” wide with curved top corners.  This creates a visual view block so each module becomes its own diorama.

Since module sizes vary, the critical dimensions are where the tracks align at the joint between the modules.  Currently all track is code 100 snap track or flex track.  The following dimensions are measured from the front (public) edge at each joint.

• Track center lines are 5”, 7”, and 18” from the front edge.
• Most modules use cork road bed on top of the plywood surface.
• The first 2 tracks are at the surface of the roadbed.
• The third track is 4” above the surface as measured rail head to rail head.
• Each track starts with a 3” piece of snap track located about 3.03” from joint.  The extra space is so a 6” piece of snap track can be used to join the tracks without binding or buckling track.  This dimension is not consistent on all our modules so we have some special connectors at 6” +/- 1, 2, or 3/16” long.
• On a 4’ straight module, the remaining track is a 3’ length of flex track trimmed slightly to fit between the 3” snap track piece at each end.  Note that the 3” snap track pieces allow for easy installation of the connector pieces and do not allow the rail to slide during setup and take down, vs. the movable rail in flex track than can slide out.
• For the corners, tracks start the same way as above, but the space between the 3” pieces is laid with curved flex-track.  The first track is on a 37” radius, second a 35” radius, and third (raised) track on a 24” radius.  This arrangement allows for longer equipment to run well on the lower tracks, and 50’ or shorter equipment to run OK on the upper track.
• Power to the tracks is fed through 6 pin molex connectors and 18 gauge lamp cord to 3 MRC Tech II 2500 power packs mounted on a plywood base.  The corner modules have molex connectors near each end (male and female) and 2 extension cables exist to feed power to the corners for larger setups.