1923 marked a major change to the organisation of Britains railways. By an Act of Parliamanet, The Railways Act of 1921, four large regional railway companies were formed by the 'grouping' of the many small local railways into larger networks. The intent was to move away from local competition between railway companies and reduce duplication of lines and services in order to make the railways better able to compete with the road carriers which had been established using 'war surplus' lorries. Full nationalisation had been considered, but Sir Eric Geddes, a highly experienced railway manager and former Deputy General Manager of the North Eastern Railway, then serving as Minister of Transport foresaw problems with government control, particularly with politcial inteference and the potential that the loss of market pressure would lead to poor or lax management control.
In terms of wagons the year also marked the major overhaul of the design ands construction rules for railway wagons, as issued by the Railways Clearing House.
In 1923 a major update to the RCH wagon specifications was published. This covered all types of wagons and generally represented an updating of the rules to incorporate new techniques and push wagon builders and owners to steadily improve their wagon fleets. The 1923 specification was to be the last major revision issued, however many revisions were made through the 1930s as new wagon designs and construction methods (eg. welding) emerged.
The preceding 1907/1909 design which had started along the path to all builders using major components of standardised or compatible design and fitting, so a broken component could more easily be replaced with an equivalent part from another builder. This greatly simplified 'on the road' repairs so wagons spent less time awaiting parts and more time earning revenue for their owners. The 1907 design also required continuous or through drawgear, a system whereby the drawbar behind each hook was extended into the central box of the underframe, so pulling forces were transmitted through the iron or steel drawbars instead of being transferred to the wood frames of the wagons. The design of many of the components was also started along the route to standardisation in design and fitting, allowing wagons to be repaired from a smaller range of RCH fittings in place of parts to the original builder's unique design.
The new 1923 wagon continued along this route with the majority of components now becoming interchangeable 'RCH standard' parts. The through drawgear was toughened up, with two steel rods running the length of each wagon between the coupling hook base plates in addition to the extended drawbars.
The new mineral wagon designs were larger than previously with the smallest 8 ton type of the 1907 specifications was eliminated from the standard lists (though still allowed in the 'small print') and more variants were made available, including a taller 8 plank body design and larger 16 and 20 ton capacity wagons, some proving more successful than others!
The basic wagon length was increased to 16ft6in over headstocks, verses the 15ft length of the 1907 design. Widths remained almost the same as these were governed by clearances of mechanical handling plant already installed to suit the earlier standards. Width over headstocks was a nominal 7ft11in (these could be tapered at the ends) with a maximum overall width of 8ft6in, however wagons to 'Bristol Channel Ports' (mostly the South Wales coal shipping ports) were restricted to a maximum width of 8ft3in. Wood or steel could be used to construct the underframes, with wood remaining popular for private owner and mineral wagons, but the more durable iron and steel underframe was to become a more frequent choice through the 1930s and with the railway companys themselves.
One major technical change implemented was the specification of oil lubricated axleboxes as standard, this being the result of successful designs of spill-proof axleboxes being commercial available, Oil lubricated axleboxes added cost, but ran much more freely and needed much less maintenance than the grease lubricated design, but previously the oil could have been lost when wagons were emptied by tipping, resulting in damage to both bearings and axle journals.
The standard lower capacity for the 1923 wagon was now 10 tons for a 5 plank wagon and 12 tons for 7 or 8 plank height. Later many of these wagons were uprated to 13 tons load capacity. In addtion to prvate owner wagons the proven RCH designs were adopted by several of the new, large railway companies for their mineral wagon fleets. The LMS and LNER both selected the RCH 1923 7 plank design as their standard mineral wagon, building many thousands, with the SR ordering a small number for their requirements in the much smaller Kent coal field.
Outside of the common 7 plank coal wagon design the RCH had authorised a wagon of 17ft6in length for coke traffic and this length was now made a standard for a 16 ton capacity wagon with 9ft wheelbase wood frame. This design proved less than satisfactory however, both LNER and Gloucester built wagons quickly developing hogged backs, though similar LMS built wagons did not seem to suffer this fate.
The 17ft6in underframe was widely adopted by the four railway companies after 1923 for their merchandise wagon fleets, with most companies opting for steel construction. A number of changes and developments were to be incorporated through the 1920s and 30s, including the change to 10ft wheelbase for merchandise wagons, this being better suited for running in fast goods trains.
The success of the RCH 1923 wagon design is evidenced in the longevity of its' basic design. In the 1950s British Railways selected the 17ft6in length 10ft wheelbase RCH steel underframe as the basis for their standard wagon fleet, while around 250,000 16 ton capacity steel bodied mineral wagons were built on the 16ft6in length 9ft wheelbase steel frame originating with the 1923 RCH specification.