Bonnet Door Progress

Door Fabrication

As stated in a previous post, it has been decided to initially restore the locomotive to the state in which it was delivered to the Strathspey Railway with flat bonnet side doors and "Queen Anne" whisky advertisements.  This means that the original bi-fold doors (which are more difficult to fabricate) can be made and fitted later, and also means the loco looks the same as the recently-released Hornby 00-gauge model.

The side sheets have been cut from 1.5mm steel sheet and the top edge folded over at 90 degrees.  Sections of 6mm steel strap have also been cut and bent and these will be welded together to form a rigid frame under the steel sheet.  Some lengths of continuous steel hinge have been obtained and cut to length and drilled to fit the locomotive.  The remains of the old hinges which were part of the bonnet and rusty and distorted have been cut off  leaving a straight edge to the bonnet.

LH Door sheet temporarily clamped

RH Door sheet temporarily clamped

The hinges have been bolted to the bodywork and the side sheets trial fitted using clamps.  The appropriate dimensions for the doors have been obtained by referring  to a number of old photographs of Queen Anne, as we no longer have the old doors to refer to.

Detail of the continuous hinge

The original "Queen Anne" doors were propped open using hinged rods bolted the the running board.   This would have been slightly awkward to use, not to mention the risk of the bonnet door falling on one's head.  For the new doors a gas strut will be employed on each side.  Using a gas strut means that the doors will slowly self-open once pulled beyond a certain point and slowly self-close after being pushed back.  The force required to open and close the doors is only a few kilogrammes - much less than the weight of the doors.  Fortunately there is a website with a very good online calculator that allows you to design your own gas strut system.

The original Ruston bi-fold doors were much lighter, as there were 2 doors on each side.  The design was quite clever - when opened the rolled bottom edge of the door could be hooked behind the edge of a channel running down the middle of the bonnet to retain the door in the open position.

A bi-fold door in the open position

Wheels

The wheels have now been needle-gunned / wire brushed to remove the old paint and primed.  This was the only part of the locomotive that had not been cleaned up.

Newly primed wheels