Dave Holt
Western Thunderer
As a relative newcomer to WT, I hope this is the appropriate place to write about my latest loco building project, which is to finally complete a model which has remained part done for quite a time. If it should be posted in "Workbench", I'm sure someone will advise me accordingly.
Early in my loco modelling life, I maintained the discipline of not starting a new project until the previous one was complete. Unfortunately, I failed to maintain this situation and ended up with several part completed locos in various states. A year or so ago, I resolved to finish these off before starting anything new and the Ivatt is the last to be tackled, despite probably being the first one started. Unfortunately, I didn't date my earlier sketches or notes, so I'm not entirely certain when this loco was started, but I found a letter relating to possible etched pony trucks dated 1995! I'm not sure if physical work had commenced, then, but I was clearly thinking about it and making detailed plans. I'm always amazed when people post about locos assembled in a matter of weeks, but even by my standards, this has dragged on a bit. Quite a few locos have been built during the period since this one started but this could still be a record for an extended build.
The basis for the model is a Bachmann body, which will be suitably modified and detailed, mounted on a chassis made from a Comet kit. The loco reached the stage of being a runner many years ago but never progressed to have the cosmetic details added. Here it is in that condition, with its near sibling BR Standard version partially visible in front.
The BR Standard was completed late last year and appeared in its final state in my first post in the Newcomers section.
Work to complete the Ivatt has concentrated so far on finishing off the chassis by adding such items as buffer beam gussets, front and rear steps, sand pipes and the injectors and associated piping. A number of these details have been made with the aid of custom etchings, produced from my sketches, by Rumney Models.
Except for the cylinder drain cocks, all the chassis parts are now completed, ready for painting. The following photos show the whole set of parts and some of them in detail. I hope they are of interest.
First, the set of components.
The frames are arranged to provide fully floating compensation for the driving and coupled axles with the pony trucks being sprung against bearing pintles, fore and aft - as per the real thing. The frames also carry the steps, injectors and piping, steam heating hoses, the pick-ups (which bear on the tops of the driving wheels) and Alex Jackson couplings.
The injectors were rather fiddly, consisting of twenty odd separate pieces as no suitable commercial casting are available, as far as I know.
Wherever possible, I try to use a removable keeper plate to retain the driving and coupled axles, as in this case. The keeper also carries the rear sand boxes, sand pipes and their support brackets, ash pan and hopper operating mechanism and, in this case, the pony truck pivot points.
The brake rigging is spit into two sections because, inconveniently, the rear, single pull rod has to pass through the "A" frame of the rear pony truck. The front section becomes entangled with the front sand pipes and brackets, meaning the two assemblies have to be juggled into place together. Inconvenient, but unavoidable.
The cylinders and valve gear are assembled as a single unit, which also includes the motor torque reaction arrangement. The up-stand has a pivoted link which connects to the gear box, preventing rotation of the latter but allowing for suspension movement. I've tried to represent the support brackets and integral splashers on the slide bar braket and reversing shaft supports.
The driving and coupled wheel sets are Alan Gibson parts but fitted with modified Ultrascale crank pin bushes. The balance weights are again custom etches as all the readily available items were the wrong shape and size.
Finally, the two pony trucks. Unfortunately, my 1995 discussions about etched version came to nothing, so in the end, I had to make my own, using the basic Comet "A" frame with hand made parts to turn them into representations of the spring and swing link side control types fitted to these (and the BR Standard) locos. For whatever reason, the Ivatt appear always to have the swing link at the front, whereas the Standards had the spring control at the front. This latter type was also used on Ivatt and BR Standards with just a front truck (2-6-0's, 2-6-4 tanks and 2-10-0's). Subsequent to me making these trucks, Brassmasters produced the spring control type for their Flying Pig chassis and I used these (one modified to represent the swing link type) on my BR Standard 2 tank, which save a bit of work. The trucks have the axle sprung with two hair pin wire springs, reacted against the bering pintles previously mentioned.
So, just the drain cocks to do, then onto the body. Needless to say, there doesn't appear to be a commercial source for the style of drain cocks fitted to Ivatt locos, so scratch building will be required. Fortunately, I had to do the exact same cocks on my Caprotti Black 5, so I at least have an idea how to replicate them this time.
Dave.
Early in my loco modelling life, I maintained the discipline of not starting a new project until the previous one was complete. Unfortunately, I failed to maintain this situation and ended up with several part completed locos in various states. A year or so ago, I resolved to finish these off before starting anything new and the Ivatt is the last to be tackled, despite probably being the first one started. Unfortunately, I didn't date my earlier sketches or notes, so I'm not entirely certain when this loco was started, but I found a letter relating to possible etched pony trucks dated 1995! I'm not sure if physical work had commenced, then, but I was clearly thinking about it and making detailed plans. I'm always amazed when people post about locos assembled in a matter of weeks, but even by my standards, this has dragged on a bit. Quite a few locos have been built during the period since this one started but this could still be a record for an extended build.
The basis for the model is a Bachmann body, which will be suitably modified and detailed, mounted on a chassis made from a Comet kit. The loco reached the stage of being a runner many years ago but never progressed to have the cosmetic details added. Here it is in that condition, with its near sibling BR Standard version partially visible in front.
The BR Standard was completed late last year and appeared in its final state in my first post in the Newcomers section.
Work to complete the Ivatt has concentrated so far on finishing off the chassis by adding such items as buffer beam gussets, front and rear steps, sand pipes and the injectors and associated piping. A number of these details have been made with the aid of custom etchings, produced from my sketches, by Rumney Models.
Except for the cylinder drain cocks, all the chassis parts are now completed, ready for painting. The following photos show the whole set of parts and some of them in detail. I hope they are of interest.
First, the set of components.
The frames are arranged to provide fully floating compensation for the driving and coupled axles with the pony trucks being sprung against bearing pintles, fore and aft - as per the real thing. The frames also carry the steps, injectors and piping, steam heating hoses, the pick-ups (which bear on the tops of the driving wheels) and Alex Jackson couplings.
The injectors were rather fiddly, consisting of twenty odd separate pieces as no suitable commercial casting are available, as far as I know.
Wherever possible, I try to use a removable keeper plate to retain the driving and coupled axles, as in this case. The keeper also carries the rear sand boxes, sand pipes and their support brackets, ash pan and hopper operating mechanism and, in this case, the pony truck pivot points.
The brake rigging is spit into two sections because, inconveniently, the rear, single pull rod has to pass through the "A" frame of the rear pony truck. The front section becomes entangled with the front sand pipes and brackets, meaning the two assemblies have to be juggled into place together. Inconvenient, but unavoidable.
The cylinders and valve gear are assembled as a single unit, which also includes the motor torque reaction arrangement. The up-stand has a pivoted link which connects to the gear box, preventing rotation of the latter but allowing for suspension movement. I've tried to represent the support brackets and integral splashers on the slide bar braket and reversing shaft supports.
The driving and coupled wheel sets are Alan Gibson parts but fitted with modified Ultrascale crank pin bushes. The balance weights are again custom etches as all the readily available items were the wrong shape and size.
Finally, the two pony trucks. Unfortunately, my 1995 discussions about etched version came to nothing, so in the end, I had to make my own, using the basic Comet "A" frame with hand made parts to turn them into representations of the spring and swing link side control types fitted to these (and the BR Standard) locos. For whatever reason, the Ivatt appear always to have the swing link at the front, whereas the Standards had the spring control at the front. This latter type was also used on Ivatt and BR Standards with just a front truck (2-6-0's, 2-6-4 tanks and 2-10-0's). Subsequent to me making these trucks, Brassmasters produced the spring control type for their Flying Pig chassis and I used these (one modified to represent the swing link type) on my BR Standard 2 tank, which save a bit of work. The trucks have the axle sprung with two hair pin wire springs, reacted against the bering pintles previously mentioned.
So, just the drain cocks to do, then onto the body. Needless to say, there doesn't appear to be a commercial source for the style of drain cocks fitted to Ivatt locos, so scratch building will be required. Fortunately, I had to do the exact same cocks on my Caprotti Black 5, so I at least have an idea how to replicate them this time.
Dave.