RosiesBoss Posted February 19, 2015 Share Posted February 19, 2015 Introduction As noted in many previous posts, I love to “tinker”, especially when there’s a bit of a challenge. Among other projects, I have enjoyed motorising several plastic kits of Kitmaster or Airfix origin or using their components to construct other models: 3440 City of Truro 3265 Tre Pol and Pen 3314 County of Chester (All 3 4-4-0s here: http://www.rmweb.co.uk/community/index.php?/topic/70438-gwr-4-4-0s-on-carmarthen-junction/) 2251 class (Post #3 here: http://www.rmweb.co.uk/community/index.php?/topic/70550-carmarthen-junction-miscellena/ ) 0-6-0 diesel shunter (http://www.rmweb.co.uk/community/index.php?/topic/59875-motorising-kitmaster-08/) GNR Stirling Single No 1 (http://www.rmweb.co.uk/community/index.php?/topic/67037-motorising-a-kitmaster-stirling-single/) Park Royal railbus (Post #5 here: http://www.rmweb.co.uk/community/index.php?/topic/70550-carmarthen-junction-miscellena/ ) I’ve also taken time out to improve simple Tri-ang starter locos such as: http://www.rmweb.co.uk/community/index.php?/topic/95885-makeover-of-tri-ang-north-british-shunter/. Recently, GBL static models have begun to appear in my local newsagent, with that of the City of Truro appearing in early Jan 2014. I had a quick look at it and decided that I would enjoy using it to kitbash a City class in its final condition – late 1920s to withdrawal around 1929-31. I therefore took one home and, within 5 minutes of opening the package, dismantled it completely. It was never designed for easy motorisation! It had a solid die-cast chassis under both the loco and the tender, with the wheels cast integrally. It was a similar tale for the front bogie. Nevertheless, the plastic mouldings are crisp and made of a good quality resin that is easy to carve and re-shape. I suppose I could have mail-ordered and then adapted a Branchlines conversion kit, but I decided to take a more cost-effective route by I following a similar approach to that used for my original City of Truro project, using a cast chassis block from an ancient Tri-ang model, with whatever other components I had in my scrapbox (many of which had been bought over the last 40 years “just in case”). Objectives Create a working model from the static one, re-using as many components as possible. Avoid purchasing extra bits. Materials GBL model Cast chassis block from Tri-ang M7 0-4-4T Hornby A4 front bogie (X5285BK) Hornby Grange tender wheels (X9357) 4 x 26mm dia Romford driving wheels 2 x Romford extended axles 4 x brass Romford axle bearings 4 x outside cranks, fabricated from modellers’ brass strip and 12BA stainless steel bolts Romford 40:1 gear set Mabuchi motor (interchangeable with Hornby Type 7) Coupling rods, adapted from the Tri-ang M7 ones Small and medium brass handrail knobs 26 SWG (0.3mm dia.) phosphor bronze wire Modelmaster name/numberplates HMRS Pressfix transfers Humbrol enamel paints Replacement brass whistles RH drive loco crew (Preiser 14014) Marker lamp (Springside) Destruction/Construction The GBL model came apart easily, held together mainly by self-tapping screws and a small amount of glue. Everything possible was stripped off the footplate and then a rectangular hole was cut to accommodate the M7 chassis block. I noted that, unlike the outside frames of the Airfix/Dapol model, those of this model are moulded integrally with the footplate. I therefore chose to leave them as they were and ultimately provide a slot at the bottom of the bearing hole, similar in principle to the solution adopted for Keyser models (such as 3283 and 2620, in my collection). This would facilitate removal of the body from the chassis for periodic maintenance and adjustment and conserve the strength of the footplate. The M7 chassis block began by looking like this (as first acquired): It was modified by removing the original wheels and rear extension and trimming the casting to suit the footplate. (Incidentally, a Nellie/Polly chassis could have been used, but these are lighter, being fabricated, not cast.) The brass bearings were fitted to the chassis and the driving wheels were then temporarily installed, using conventional axles, as I did not want to foul the (as yet) unmodified outside frames. I then checked whether a spare Tri-ang X04 motor would fit inside the body without too much cutting away: it wouldn’t. The chassis block was therefore modified to take a small rectangular open-frame Mabuchi motor. This work included fabricating small brass brackets to hold it securely in place and provide perfect meshing of the gears. I returned to the footplate, which needed some way to locate it onto the chassis. I realised that this could be done by fitting a brass bracket to the front of the chassis (to locate onto the footplate just behind the smokebox base) and by using the screwed fitting under the cab. Once these were completed, I relieved the inside of the wheel splashers to eliminate fouling of the driving wheels, using a tool similar to a dentist’s burr, fitted to my miniature drill. I also removed all of the attachments for the dummy front bogie. Parts of the underside of the boiler casting were cut away so it would fit over the motor. This also opened up the front half of the boiler so lead weights could be eventually inserted to improve traction. The front bogie, as supplied, was useless. However, the dummy outside frames are very nice, so I removed them and cut away the spigots that had held them to the cast bogie wheels. I found that a spare Hornby bogie had exactly the right wheelbase. It is fitted with 14 mm dia wheels. I did experiment with a set of 15 mm dia wheels (the correct scale size), but these fouled the footplate and hence the model would not go around curves. A brass spreader was fabricated to go across the top of the bogie and the dummy outside frames were then glued to this. A brass mounting arm, similar in principle to those seen on many Tri-ang and Hornby models, was made but with the additional feature that, with careful adjustment after completion of the rest of the model, it functions as a gentle spring, to support the weight of the boiler in order to ensure that all four driving wheels remain in contact with the rails. Here’s an image of the new bogie compared with one from a Tri-ang Dean Single: At this stage, the chassis looked like this: Once all of the running gear was complete, all moulded handrails were carefully removed in preparation for their replacement with metal handrails and knobs. I now turned my attention to the tender. As supplied, the tender comprises three main assemblies: tender top, dummy frames (both moulded plastic) and brake-gear/wheels (die-cast metal). Apart from the moulded handrails and odd rear lamp, I was happy with the plastic components, so made minimal changes here. Because the working model needed something to mount the Hornby wheels on, as well as some ballast to provide stability when running, I chose to modify the metal piece by grinding off the fixed wheels, cutting a slot on the upper side in line with the axles, and drilling/tapping some 12BA holes for bolts to hold the axles in place. These bolts are fixed with black nail polish – sufficiently stiff for normal operation, but adjustable if necessary. Re-assembled, the tender looked like this: I returned to the loco chassis and replaced the temporary inside-frame main axles with extended axles. I then carefully cut slots in the outside frames to accommodate the extensions. I also removed the dummy outside cranks and coupling rods, planning to fill any holes with automotive body filler. I then soldered the cranks to the extended axles, quartering them by eye. The M7 coupling rods were modified by soldering brass behind the bearing holes and then drilling fresh holes of a size just large enough for the 12BA bolts mounted on the cranks. These were then test fitted to the cranks and adustments made both to quartering and to their holes until the chassis ran freely. A simple pickup system was fabricated from an offcut of printed circuit board and phosphor bronze wire, screwed to the bottom of the chassis in the place provided by Tri-ang, using a non-conductive plastic 8BA screw left over from an ancient Keyser kit. The plastic coupling bar at the rear of the footplate was cut off and a slot carefully made in the centre at the bottom of the spreader. A new brass coupling, pivoting on the rear body-mounting screw, was then fabricated. Lead ballast weights were then assembled from old sheet lead offcuts, just enough to fill available space in the smokebox and boiler. The loco, dry-assembled, now looked like this: I fitted a narrow (Bachmann) tension-lock coupling to the tender using a pair of 10BA bolts and nut-locks. It was now time to tidy up the bodies – before re-assembly. I began by removing the front lamp irons and whistles, then drilled the bodies for new whistles, handrails and knobs, where appropriate. Knobs and whistles were commercial items. Handrails were made from 0.3mm dia. (26 SWG) phosphor bronze wire, left over from constructing the overhead wire system of my H0 tramway: http://www.rmweb.co.uk/community/index.php?/topic/77505-rosemount-tramway/. The smokebox door handles were corrected by carefully removing the redundant (third, vertical) handle. New front lamp irons were made from household staples. Body blemishes/holes were filled with automotive body filler. The model – dry-assembled - now looked like this: Painting began with the dismantling of the body parts from the chassis and the spray priming of those parts. Chassis parts were brush primed. The loco was then painted in post-1923 green and black, left unlined. (The inspiration for its finish is the image of 3712 in Plate 53 in Ref.3.) Once the paint had fully cured, the body was re-assembled (glued where necessary) and then restored to the chassis. I chose to rename the model “City of Chester” – the birthplace of one of my great-grandmothers. New name- and number-plates, crew, coal, marker lamp as well as new HMRS transfers were then applied to finish the model. The model was then tested under power, adjusted to cure any stiffness, and then given its head on the layout. Reflections This model was indeed modified using components already to hand. The only items purchased specifically for it were the name- and numberplates. The ease with which this project went forward confirmed the wisdom in gathering miscellaneous parts over the years when they were available at a good (usually discounted) price. Some of them are now quite difficult to find, as many suppliers have disappeared. I have been so impressed with how easy it has been to modify this GBL model that I have bought another CoT for future spares and am on the lookout for further models in the series that may be of use for additions to my collection. Is it a “museum quality” model? No, but if it were, it would look out of place with the rest of my collection. As it is, it fits in well enough and is able to haul a typical load for an engine nearing the end of its service life, as shown here: http://mikemorant.smugmug.com/Trains-Railways-British-Isles/GWR-and-BRW/GWR-4-4-0s/i-xc8RDQn. I did enjoy working out how to make it a functional model – not just a pretty toy to leave on the mantelpiece. I do prefer the satisfaction of seeing my own work gradually materialise into a working model, rather than simply opening a box to put the model on the track. How much did I spend specifically to complete it? $19.95 at the newsagent plus about $20 for the Modelmaster name/numberplates (including air mail from the UK) – say around A$40 (ie about GBP20). I think it compares pretty well with the local price of a Bachmann “City of London” - A$310. I’m happy with the discount! References Anon: The locomotives of the Great Western Railway – Part 7 – Dean’s Larger Tender Engines (RCTS, 1954) John Lewis et al: Great Western Way (2nd ed., HMRS, 2009) Maurice Earley: Truly the Great Western (Oxford Publishing Co., undated) Link to post Share on other sites More sharing options...
Londontram Posted February 19, 2015 Share Posted February 19, 2015 Out standing work and what a fine looking loco you've gained for your fleet and the enjoyment and satisfaction you must have got from building it is unmeasurable. Real modeling at its best. Well done Steve Link to post Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.