10.20.2008

portly porter problem?

Dad purchased a Bachmann On30 porter (0-4-2) to use on his proposed 7mmNG, Welsh quarry inspired portable layout. From KeyKits in the UK, we obtained suitable Anglicising pieces (Wrightlines W996 cab kit and W963 chimney). The conversion itself was prompted by Brian Fayle's 7mm micro-layout workhorse and other examples from his website. The Bachmann chassis is a known "good runner" so we anticipate good service.

It did run well right out of the box, however, once the whitemetal cab pieces were substituted for the plastic details, the ends of the siderods started banging into the underside of the cab floor. "Too much weight!" was the initial thought but, upon partial disassembly, it was observed that one of the rear axle U-grooves in the plastic frame was deeper than the other. This caused the rear axle to tip out of true with respect to the front axle and the engine developed a list to one side.

This tilt caused the engineer's side of the cab floor to interfere with the siderod motion. ACC'ing a ~.015" thick pad of shim brass at the bearing surface of the over-deep U-groove solved the problem. Now the engine sits level on its axles and travels without any apparent binding.

The new cab assembly is secured to the stock footplate with flat head 1-72 machine screws countersunk into the underside of the floor. A stemwinder brake stand has been added to the footplate. The Bachmann steam dome needs to be removed from the saddle tank, and a simplified water fill hatch needs to be fabricated. The engine can then be painted and lined for service.

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