Thursday, 16 August 2007

Heath End - Trackwork

Four different track types are used on the layout: plain track on the main line and loop is C&L bases with Society BH rail, and the long goods siding is Exactoscale bases with full-depth sleepers, which had recently become available when we started so we wanted to try it. Visible pointwork uses the traditional Brook-Smith ply timbers with brass rivets, to which we [will] attach cosmetic C&L ½ chairs. The FY section was constructed in one piece using the simpler method of PCB sleepering, and then isolating gaps were cut where needed.

All the trackwork was first designed and printed out using Templot®, and points built directly on the templates printed. This is an excellent design product, and though it takes some time to master all the features, it is worth it. The only thing that defeated it was the diamond on the curve in the FY, with a crossing angle of 1:3.5!! I just had to superimpose the two curved plain track templates, and leave our veteran point-builder Allan Smith to put in the check rails where they were neeeded! Point tie-bars use fine PTFE tubing with short wire stubs soldered to the rails and inserted into the tube to ensure insulation and positive closure. Remote operation is by wire-in-tube from DPDT switches that change crossing polarity: fine adjustment is achieved by using brass studding through the switch and nuts on each side, so that the excessive switch throw is taken up - rather like the old omega-wire. Crossovers are operated from the same switch.

Trackwork is laid on 3mm cork sheet: the sheet is glued in place, and the track laid on using commerical double-sided tape. The accuracy of curves was achieved using home-made 'track-setters', glueing a Templot® template onto vinyl mounting board and cutting out carefully with very sharp blades. Thus both outer [49"] and inner [47¼"] radii gauge-width templates plus curved 'six-foot' ensured accurate alignment. Sleepers and rail sides were painted appropriate colours and ballast applied dry, and fixed in place using a water-PVA mix. To assist vertical alignment at baseboard joints, a brass nail inserted into the board on the inside of each rail [to hide it from the public!] is soldered to it . All this, and we still get alignment problems here and there!

The next instalment will deal with the level crossing; in the meantime, I will upload a few photos for light relief!

No comments: