SM32 Sand Pit

The layout was constructed in 1998 by Don Mathers and Ken Kemp to produce a large scale layout which could be operated in an automatic mode requiring little attention and no operator. This made it necessary to operate with electricity rather than Steam as is the case with the main SM32 layout. The final decision was to construct small industrial type diesel/petrol loco’s with internal batteries which could be re-charged. This came to pass by the donation of several battery Screwdrivers with battery packs that run at 4.5 volt and some rudimentary gearing.

The chassis of 3 loco’s were constructed using simple brass side plates to carry the motor, gears, axles, and re-chargeable batteries. They incorporated a micro switch under the chassis to stop the loco on a ramp operated by a H&M point motor under the track. A side tag was added to operate external switches to detect their position and operate external equipment.

The baseboard was produced in two pieces of 5 foot square which was designed to house all the electronics underneath and all the scenic appearances of an industrial gravel plant and shipping point on the top.  The requirement to have all the scenic parts removable so that the boards could be stored face to face was designed from the beginning.

The track was designed to form a folded figure of eight using coarse scale “O” gauge track constructed by hand from old track sections mounted on 5mm ply sleepers cut on a band saw. We added trailing points operated by the loco wheels and leading points operated by H&M motors triggered by the loco side tag operating a trackside micro switch which sets the route.

The layout incorporates a shipping dock with a coaster ship with open holds and a tippler mechanism to empty 4 side tipper wagons into the holds. This then led to a problem as ordinary sand jammed the loader. We used silver sand which solved that problem but raised several more in the future.

The loader and tippler is also operated by the loco’s side tag detecting the trains position at each stop. First the wagons are loaded one at a time with a measured volume of sand and then unloaded two at a time at the dock. The intention is to transport the load under the layout with a bucket unit back to the loader but this is yet to be completed. The sand is at present collected in a half gallon container and transferred by hand to the loader at aprox 4 hour periods.      

The layout is designed to operate two trains at a time with four wagons in each train with one spare loco for recharge periods. The train at the loader is the initial sequence starter for one complete cycle discharging both trains into the coasters hold.

Unfortunately, the Sand used found its way into some of the critical parts of the mechanism and as such, we are looking for alternative loads. The layout operated (with reasonable success) at the 2018 exhibition using round beads but these too were not without their issues as they had a habit of escaping and rolling across the floor!

The layout will return in 2020 – choice of aggregate is still to be decided! Any suggestions gratefully received….

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