Russian 50T Boxcar EPII

thingiverse

Soviet 50T Boxcar Epoch II (referred to as GGru) – Version 2 (25/03/2020) I've been creating a 13.5 meter, 50 tonne SZD boxcar in 1/160th scale as per EpochII. I'm using SZD declassified blueprints found through Russian websites and a declassified CIA document! I also used photographs from Russian and German sites to get the feel for the prototype which I've never seen myself! I created the design using Openscad (version post May19) with dimensions from prototype blueprints scaled up. The design has three components, body, chassis, and roof. There are four Openscad files: one for the body, one for the chassis, one for an axlebox, and a common file for constants. I've provided several options in the parameter file to select truck and coupling. Although I tried to make the design scale independent, compromises were needed to fit 1/160th scale. I also attempted to make it modular so variants can be easily accommodated. Any redesign should be checked before printing. I use slic3r software to translate resulting .STL files to GCODE. I'm using a BQ Hephestos printer with a heated bed and a 0.2mm nozzle. PLA filaments are used for the print, black for the chassis, dark brown for the body, and dark grey for the roof. The chassis has been designed to resemble the prototype but compromises were made to create a strong component. I've designed it to use MicroTrains 1011 Archbar trucks as a design close to the prototype period. Later, post-wwII might use Bettendorf trucks. This design uses MicroTrains 1016 medium shank body mount couplers, giving a moderate space between wagons which will accommodate buffers. It's possible to use MT1015 short shank body mount couplers if layout radii permit. Mounting the assembled MT1016 couplings into their printed box is a tight fit and may need easing. I've tested this design with MT 1010 Archbar trucks fitted with short shank couplers. Wagons are close coupled but negotiate R3 curves. The central spine portions of the chassis near the wagon ends have been removed to clear the truck coupler boxes. Some adjustment may be needed to the buffer beam to clear the Micro Trains coupler pin. No allowance has been made for Rapido type couplings, which may be a future revision if desired. As implied above, provision has been made for traditional buffers as the SZD was converting from 3-link to SA3 couplers during EPII. Some boxcars retained buffers after conversion to SA3 as can be seen in photos. I haven't provided facility for traditional 3-link couplings. The MicroTrains trucks have been re-wheeled to use Intermountain Railway 60052 wheelsets. This may affect the underframe height above rail, so a check is needed to ensure coupling box clearance on curves. I've added simulated bodyside planking which may enhance the appearance of the design but can be commented out of the source if desired. The body uses dimensions taken as far as possible from prototype drawings but some assumptions have had to be made owing to some dimension values missing on the GA drawings. The whole design (including trucks and couplings) weighed 10 grams in 1/160th scale and will require some weight to be added to ensure good running. I suggest adding 8-10 grams for an all-up weight of 18-20 grams in 1/160th scale. I consider this design as complete apart from a design of the air-brake control valve. I hope it will be useful and I welcome improvements.