by Doug Hewson

FEB 2012. I thought it was time for another update on the GWR 5700 loco project, although I have not quite completed the full set of drawings yet. However, I had an excellent email from Matthew Pulzer who pointed me in the direction of his super photos which were taken underneath 3786 while it was over the pit at Didcot.  This has allowed me to study all the detail clearly of the drain cock linkage and work out how to do it on the 5” version. 

I am now trying to complete Drg 5. which will show that linkage.  I had one detail missing and that was how the rod got from the drain cock lever to the diagonal rod inside the frames where it connects to the linkage under the motion bracket.  However, I decided to look again through some other photos which John Branrick kindly sent me of Panniers in action in steam days plus quite a few of Panniers in various states of repair in Swindon Works.  Most of the shots were of a general nature but there was one photo of a detail and it just happened to be the small shaft mounted in a trunnion on top of the middle right hand splasher where the rod changed from outside the frames to inside so the problem was solved.  I am very grateful to John for that.

The new laser cut kit for the footplating has arrived and Frank Osgerby has got his all fitted, without any problems I am told.  It was all fitted and painted in ten days!  I don’t know what kept him!  The kit includes the splashers step plates and steps plus I have added the lamp irons since then.

The laser cutting drawings for both bunkers and cabs (5700 and 8750) are now complete and have been sent off for pricing.  I have also sent off the wheel drawing for a price for a new pattern.  The other laser cut parts which have arrived are the frames, balance weight set and buffer beams.  The frame plate set also includes guard irons, reach rod, coil spring plates, horn keeps and the reversing lever for the weighshaft plus lifting links.  There is also a laser cut set of parts for the reverser including the notched quadrant plates and mounting trunnions.

The other drawing which I have completed is the laser cutting drawing for the kit of parts for the frame stretchers, platform brackets, buffer beam brackets, drag box stiffeners and outside brake pull rods.  This has also gone for pricing.

The up to date drawings list is:-

  1. General Arrangement

  2. Frames, motion bracket and axleboxes

  3. Frame stretchers, brake cylinder, buffers, buffer beams part brake gear

  4. Frame plan, more brake gear

  5. Sanding gear and boxes, lubricator, drain cock arrangement and gear.

  6. Cylinders, wheels, coupling and con rods

  7. Valve gear arrangement and details and reverser

  8. Smokebox, regulator, safety valve cover

  9. Tanks and tank cover plating

  10. Boiler, ash pan, damper, fire grate & top feed

  11. 5700/11, 5700 bunker (for 8750 class order drawing 8750/11)

  12. Cabs platework, both types

  13. Cab arrangement, boiler mountings, drain cock lever and whistle

  14. Boiler fittings/ combined steam/vacuum brake valve, dome cover, gauge glass (not complete yet)

I have also decided to use the hollow stay as a steam pipe to the smokebox (rather than an exhaust pipe for the ejector) and to use a simple vacuum ejector inside the smokebox which can exhaust up the chimney.  A friend of mine tried using the hollow stay as an exhaust for the ejector but there was too much back pressure in the stay for the ejector to work effectively.

I also received an excellent CD of photos from Guy Harding which included some excellent close detail shots and this has allowed me to complete the details of the opening windows for both the 5700 and the 8750 cabs.  At present I am just in the midst of designing some lost wax castings for the brass window frames which will be cast as a set including the hinges and catches.

The photos are of Frank Osgerby’s loco.