Turntable plans and construction

The turntable is based on a design by Nick Godfrey in the Winter 2001 Maxitrak Owners Club magazine. My plans are available as both TurboCAD and .gif files.
The 1.25 metre diameter turntable is built from 50mm by 25mm timber with 38mm by 6mm flat steel supports. It is supported by 4 castors which are glued with Araldite to the correct angle, and by a central pillar. 20mm wide flat steel bars are screwed to the sides to provide a very rigid structure.
I wanted the turntable to allow access to the engine shed, as well as turning the locos. I constructed an accurate temporary track to determine the optimum position of the turntable, and drove a steel rod in to the ground to mark the exact centre.
I dug a 25cm deep hole with 1.8 metre sides. The ground consisted of a thin layer of sand on top of 10cm of well compacted road hardcore laid on the clay sub soil. I used the turnatable laid on a concrete paving slab as a depth guide, and dug 10cm below the level required. This was then partly backfilled with the hardcore to provide a very firm and stable base.
I used four 60cm square concrete paving slabs to provide a level base. These were laid on paving mortar on sand, having again checked that the dead centre of the turntable would be at their intersection. As the land around the turntable slopes slightly, I used a long spirit level to ensure that the slabs were dead level. The mortar was left to dry for a week.
The turntable baseplate was fixed to the paving slabs using four 10mm concrete bolts, one in the corner of each slab. With the turntable back in place, I dug away further at the edges of the hole to allow space for the surrounding bricks. The area around the slabs which were to support these was filled with more hardcore and covered with mortar to provide a firm, flat base. This was left for another week to dry out and harden thoroughly.
The surrounding bricks are 60mm deep charcoal block paving. These have a 100mm width which means 40 are used to make a circle. With the turntable back in place and using this as a guide, the blocks were carefully laid on 10mm of mortar, 10 to each paving slab. Drainage channels were provided on each slab running under the the corner block to try to prevent the turntable well becoming a bird bath in wet weather.
I laid two storage tracks into the shed, one for the locos and the other for the wagons. I have not fitted a run around loop to the main line to save having to purchase an extra point (turnout). To reverse the train direction, I run the loco onto one of the storage tracks, then the wagons onto the other. The loco is driven back onto the turntable and turned to face forwards on the main line. The wagons are then turned to follow the loco.
The turntable is aligned by sliding a metal tongue from an exit track into a guide on either end.
I put a small ash pit enclosed by four blocks on one of the storage tracks. This allows me to drop Dixie's fire and roll her out of the way easily after steaming.