GWR 14XX 0-4-2 Tank Loco

22/06/2012

Last year my brother and I helped to sort out and clear a workshop for a lady whose husband had passed away (my brother bought the 2-4-4 Forney from here). Amongst the many sets of castings were those for Didcot - the 5inch gauge 14XX by Neville Evans. I decided to buy these along with a set of laser cut frames to put away for a future project. I thought it would make a very nice easy to manage loco for running at our club. There was also a set of rather poor quality drawings from Reeves. I haven't yet received the wheel castings although there are a set of driving and coupled wheels somewhere. I'm not too fussed about those as the wheel bosses on the castings supplied by Reeves (the sole supplier for Didcot) are much too large compared to the full sized versions and so I may make a pattern and get some cast. I'd like to make my version a bit closer to scale than Neville's, with the correct slide bar arrangement and valve spindle guides etc. Polly Models do a set of drawings for a 7.25" version (based on Martin Evans's Dart) which is much closer to the original so I may get a copy of those and scale them down.

At the moment I'm producing a new set of drawings using 3D CAD to find any errors in the Reeves drawings and to make sure everything fits together. I've found a few errors so far including one on the drawing for the rear sub frames. These are not deep enough on the drawings and need to be extended to ensure the trailing axle boxes are not too low in the horns. There were a set of laser cut subframes included with the castings but unfortunately they had been made to the original dimensions and so will have to be scrapped.

This is definitely a project for the future as I want to finish Simply Longer first but I'll carry on with the drawings as time permits. To begin with I'm just following Neville's design and checking that out. The modifications to bring it closer to scale will be added later. The valve gear needs modifying slightly to give better events but that is mostly a matter of offsetting the suspension pin for the expansion links. They are drawn on the centreline of the slot but need to be moved forwards by about 0.0625" to equalise the cut offs at both ends of the cylinders.

 

Drawing work so far

There are a lot of similarities between Neville's Didcot and the kit versions produced by Winson and Modelworks (in fact they are pretty much identical!) so I wonder if they used the same drawings?

21/07/2012

A bit more drawing done.

 

I notice that Model Engineer have started running a series on the Polly Model Engineering 7.25" 14XX so hopefully the drawings will be included!

 

 

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