Railway Service Crane
Born in May 1960, I obtained a copy of the appropriate Meccano Magazine. It was interesting to see a clutch design in the magazine by our own Alan Wenbourne!
The model I selected from the magazine was the set 7 Railway Service Crane on pages 252 and 253 which at first sight didn’t seem too much of a challenge. However the model had a number of significant weaknesses which I set about resolving.
- Very weak central pivot — this was easily overcome by incorporating flat plates and the Meccano ball thrust race. Instead of the toothed section I opted for a circular plate. Although some of the holes coincide with the track of the balls there are always sufficient balls in contact with the plat plate for this not to be a problem. A 95-tooth gear was employed instead of the 57-tooth gear to engage the worm gear and the pivot point moved ½” accordingly.
- Very poor balance — the jib plus any load easily toppling the crane. Use of flat plate construction and internal counterbalance weight overcome this problem.
- Cables foul on front cross member — I opted to redesign the front of the cab and dispense with the cross member.
- Dual-haul of jib without any compensation — to do the job properly would have required a differential between two winding drums. Instead I opted to use a single winding drum and cable doubled around the jib pulleys. This maintains the original appearance and works well.
- No winding braking — instead of adding winding brakes I incorporated worm gears and 19-tooth pinions preventing the loads back driving. Drive to the worms is geared up to avoid excessively slow hand winding.
- Sliding jockey pulleys were incorporated to that help consistent cable winding on the drums.
- Heavier pulley block.
- Double thickness axle bearings.
- Buffers and couplings added.
- Hinged and locked cab roof, for access and inspection.
Having completed the crane I thought it deserved a matching truck along similar chassis construction lines.
Then it needed some track to run on…
Then I added a buffer section…
Next a footbridge…
Now a locomotive and a flat-bed truck…
What next? Maybe a guards van? More track? Signal box and signals? A platform? Ticket office?