The North British Railway and the North Eastern Railway became part of the LNER (see more below)
The LMS as incorporated was the largest joint stock company in the world. Covering a vast geographic area with widely differing economies, problems and markets devolved management was essential and this entailed a high degree of continuity from the previous company organisations. In England it three main divisions were based on the territories and lines of the three largest companies - Midland, Western (largely the former LNWR) and Central (L&YR) divisions. All lines west of the Lancaster & Carlisle line were initially part of the Central Division with its headquarters at Manchester Victoria, though all were locally unified under a Traffic Superintendent at Barrow.
A degree of rationalisation was quickly achieved: within the year the former M&CR and G&SWR locomotive sheds at Carlisle Currock had closed, as had Workington Central and Workington Dock Junction, the latter destroyed by fire in February 1923; Moor Row and Maryport works closed and the shed at the latter was to follow in a few years. Company offices were closed at Maryport, Keswick and Workington. By 1930 Barrow works was much reduced with locomotives being sent to Horwich for maintenance instead. Some expensive to work and maintain duplicating lines such as the Northern Extension of the Cleator & Workington and the Solway Junction had already closed as through connections in the spirit of co-operation engendered before actual grouping.
On the locomotive livery side, the red of the Furness, the greens of the Maryport and Sou'Western, the rich blackberry black of the LNWR and the blue of the Caley were replaced, for a few years anyway, by Midland red on passenger locomotives and overall black on good engines, but from 1928 the red was reserved for express engines only. Very soon, however, the small classes of locomotives of the local companies were scrapped and replaced, first by imports of types from the LNWR, the L&YR and Midland, and then by LMS standard classes, so that by the early 1930s very few former FR, M&CR or G&SWR locomotives survived, no matter how recently they may have been constructed. The coaching stock most pre-grouping companies operating in Cumbria had displayed a variety of two-tone liveries - all to be replaced by overall Midland red.
However, during the 1920s economic conditions were to deteriorate rapidly after an immediate post-war boom, and especially in West Cumberland. Not only did demand for Bessemer steel fall disastrously but local ore resources were virtually exhausted - with coal production also falling from a reducing number of collieries in a difficult-to-work coalfield. Numbers of now obsolete iron works closed and reinvestment was desperately needed - eventually to result in the emergence of the single integrated works at Workington. The railways had been built to serve these industries and suffered accordingly with big reductions in staffing and resources. As further collieries and works closed other lines also disappeared, though the majority of the local network was to survive throughout the LMS years.
Having been built to serve local industries the railways did not in many cases serve local communities very effectively and the new and more convenient bus services very quickly eroded their passenger traffic. By the mid-1930s in West Cumberland only the coastal route and the Workington-Penrith line retained their passenger services, though elsewhere most passenger services were to continue.
Some more positive change was achieved by the LMS on the West Coast Main Line though the county - the former LNWR and Caledonian route between London and Scotland. Competition between the east and west coast routes had virtually ceased after the Railway Races of 1895, with standard eight-hour timings between London and the two main Scottish cities. Although timings were to unchanged for a few years more, competition was to re-assert itself in another way - non-stop services.
In the spring of 1928 the LNER publicised its intent to commence running the 10 am express from London Kings Cross to Edinburgh non-stop, using the corridor tender facility in its latest Pacific locomotives to enable footplate crews to be changed around the half-way point near York, this arrangement to commence from 1st May. Despite not having such a provision on its brand-new Royal Scot class 4-6-0s, the LMS pulled off a remarkable publicity stunt by running two trains non-stop from Euston, one to Glasgow and one to Edinburgh, a few days before the start of the LNER service.
Into the mid-1930s and the brakes came off competition altogether, and art deco style and design played a significant part. New streamlined locos on the LNER and new speed records were answered in style by the LMS until the LNER gained the all-time speed record for a steam locomotive of 126 mph on 3rd July 1938. Timings were cut to 6½ hours on the regular "Coronation Scot", leaving Euston and Glasgow Central at 1-30pm, calling only at Carlisle, until all was brought, if not to a halt, then to grinding slowness almost overnight when World War 2 was declared.
For most LMS express services however, Carlisle remained a frontier junction between the railways of England and Scotland. It was many years into the British Railways era that the practice ceased of changing of locomotives on almost passenger trains passing through the Border City. At the end of the LMS era Carlisle was the operating centre, not just for LMS lines over northern Cumbria, but also covering most of south-west Scotland as well.
With two of its constituents providing connections to Carlisle from North and East there was to remain divided between two areas based in Newcastle and Edinburgh. Further south in the Eden Valley the lines of the former North Eastern Railway which ventured over the Pennines were again totally separate in their function and operation. By the 1930s, however, some rationalisation was achieved in Carlisle with the closure of the former North Eastern loco shed at London Road, but otherwise changes were small. The North Eastern apple-green livery was applied to many locomotives with varnished teak finish on much of the coaching stock.
War once again brought much increased traffics with reduced maintenance and at its end left the railways in a very sorry state. A new Labour government was elected with a big mandate to nationalise "the means of production" as well as the major inland transport systems of the country, including the main line railways. This was effected under the powers of the Transport Act 1947 with vesting day being the 1st January 1948. The "grouped" railways had lasted exactly 25 years. Apart from some closures and rationalisations, changes in liveries and some modernisation of the locomotive and rolling stock fleet, the railway in Cumbria still looked remarkably like it did in 1923.