The two companies each needed approach railways at both ends of the line to connect their respective systems; these were built as part of a single project.

By the final decade of the nineteenth century, the Great Western Railway had consolidated its network, and according to one point of view, had failed to develop its business further.

This was true of the West of England and South Wales routes, and the line from London to Birmingham and Chester took a roundabout alignment by way of Didcot and Oxford.

[1][2] At the same time the Manchester, Sheffield and Lincolnshire Railway had set about transforming itself from a northern industrial concern into a trunk line, and it planned to reach London.

Sir Edward Watkin was the chairman of the MS&LR and also of the Metropolitan Railway, serving areas north and west of London, and he planned to join these lines.

The MS&LR obtained parliamentary powers for the line, from the southern end of its network at Annesley (near Mansfield) to Quainton Road, in 1893.

His successors as the prime movers were William Pollitt (MS&LR) and John Bell (Metropolitan) and their personal relationship was not cordial.

Excessive charges and an unrealistic proposal for working mineral traffic from Baker Street to the London, Chatham and Dover Railway started the downward trajectory of the relationship.

[5] He had earlier refused to allow these trains to run the relatively short distance from Quainton Road to Aylesbury until the GCR London Extension was open throughout its length.

This was compounded by Bell's absolute refusal to allow mineral traffic to be worked to the GWR at Aylesbury, nor to destinations south of London over its own system.

As well as the congestion of a suburban passenger operation, the curvature and gradients of the Metropolitan line were unfavourable, and the GCR began to consider alternatives.

The Metropolitan Railway faced losing a substantial income from running powers charges, and it had already expended considerable sums on widening its line for the GCR.

[5][7] Moreover, in 1901 the two personal adversaries each retired; Sam Fay became General Manager of the Great Central and Colonel J. J. Mellor took over at Baker Street.

The GCR would build a line 6+1⁄4 miles long from Neasden Junction on its planned new route from Marylebone (at this point independent of the Metropolitan Railway, so permitting free access to the London terminus.

This was however considered a roundabout route and the GWR now decided to build a 5+3⁄4 mile direct link from further north on the GCR part of the new line to Banbury.

[12]The ownership of the completed construction was: Greenford to West Ealing: 2+1⁄2 miles; GWR The existing Aylesbury branch of the Wycombe Railway was taken into the control of the Joint Committee.

The companies anticipated the development of new suburban housing, as had happened on the Metropolitan Railway main line, although this proved slower to take place than was hoped.

Steam railmotors were used on the London end of the line from 1903, giving the potential for frequent low-cost local passenger train operation.

[5] The line was originally intended to connect through to the Vine Street station, terminus of the earlier Uxbridge branch from West Drayton.

Although some land for the connection was acquired, the through section was never built, and the branch remained a dead end; it was two miles in length and double track until 1922, when it as reduced to single line.

It was a small bogie vehicle equipped with a 90 hp six-cylinder petrol engine driving a 55 KW multi-polar dynamo.

Fay told the press that ‘My view is that we shall see oil electric cars running on the railways and supplanting ordinary steam engines to a very great extent.'

For a period it remained in the London area, sometimes hauling an ancient ex-MS&L six-wheeled composite as a trailer, but it was unsuccessful and its last days were spent on the Great Central & North Stafford joint line in the mid-1930s.

[14][note 2] After World War I the anticipated suburban development took effect more vigorously, and in due course Harefield and Ruislip Gardens stations were opened.

[1] The LPTB in collaboration with the LNER and GWR examined ways in which the now-heavy suburban business in Middlesex might be handled, and a scheme was formulated which became part of the 1935 – 1940 New Works Programme; the GWR would build new electrified tracks from North Acton, on the Ealing and Shepherds Bush line, running alongside the Joint Line as far as Denham.

The trunk line status of the Great Central Railway London extension was viewed as an unnecessary duplication, and many of the best express passenger trains were transferred away from the route.

The Master Cutler, a prime Sheffield express was moved to the Kings Cross route in 1958 (and later still to the Midland main line).

[1] In the 1960s the loss of business on the railways was exercising government, and the Beeching Report resulted in closure of the Great Central London Extension north of Quainton Road on 3 September 1966.

During the electrification and infrastructure improvement works, Birmingham express passenger traffic was concentrated on the Western Region route over the Joint Line.

An oil terminal at Thame and a car factory at Morris Cowley kept the extremities of the route open for goods traffic for the time being.