Where did the Baker Street and St John’s Wood line get its trains – seeing it didn’t have any carriage sidings or engine sheds? Obviously these came from the Metropolitan Railway’s main depot at Chapel Street. In those days this was a substantial site consisting of carriage sidings and engine sheds where all forms of maintenance and cleaning were undertaken.
The first locomotives to be used on the St. John’s Wood line were five 0-6-0 tank engines built by the Worcester Engine Company. These proved too powerful and were replaced by standard Met 4-4-0T’s. The line’s carriages were generally stabled at Baker Street overnight. Locomotives continued to be procured from Chapel Street until a new engine depot could be built at Neasden in 1879/80.
The St John’s Wood railway was taken over by the Metropolitan on 1st January 1883. The Met Railway were responsible for a tranche of new improvements including major remodelling of the junctions and stations at Baker Street. Under this new ownership a different style of sleeper was tested on the open sections of line. These shallow trough cast iron sleepers commonly seen on European lines were made by Bolckow, Vaughan and Co, possibly to the designs by Cabry and Kinch. The Met found these sleepers made the track more difficult to maintain, especially on curves and the trial lasted only a few months.
Baker Street was remodelled in 1910-12. Parts of this work still remains to this day and is quite visible even though Baker Street station received further upgrades in the 1920’s and 1930’s. The through tracks at Baker Street to Finchley Road have always been on the same alignment as the original St John’s Wood railway. Their position is dictated by the nearby junction which obviously cannot be moved. There have been past proposals to modify and even move the junctions in order to increase capacity however these were seen as too expensive.
There is some confusion as to when electric services began on the St. John’s Wood line. Some reports say these began between Baker Street and Harrow/Uxbridge on 1st January 1905 and others say this began on 12 November 1906. In fact it was December 1904 when the first electric trains ran! This was to trial the new trains and to publicise the forthcoming new services to the media.
As the tube system expanded and the Metropolitan Railway become more busy, relief was sought in the form of an extension to the Bakerloo Line between Baker Street and Finchley Road. This was built in the late 1930’s and resulted in the closure of the original three stations on the St John’s Wood railway.

The closed Marlborough Road station.
The new section of Bakerloo Line had stations built at St John’s Wood and Swiss Cottage. The former was a direct replacement whilst the new St. John’s Wood station replaced those at Lord’s and Marlborough Road.

The closed Marlborough Road station’s stairs as seen from a passing train.
The three intermediate stations may be closed nowadays but they are needed for engineers or workmen to access the tunnels. Not only that they are also evacuation points should passengers need to detrain in an emergency.

The original St John’s Wood Road station.

More or less the same site today (given that the road layout has changed completely.)
Both Swiss Cottage and Marlborough Road still retain their original staircases for this purpose. However St John’s Wood Road/Lord’s station now has a hotel built on top and thus new staircases had to be built at the opposite end in Lodge Road giving access to that street instead.

The emergency access to St John’s Wood Road/Lord’s disused station.
When the Bakerloo’s route to Stanmore was constructed, it was a difficult job. It meant the Metropolitan Line’s tunnels had to be moved. This was problematic as as the Great Central (now of course Chiltern) also ran beneath Finchley Road south of the station which meant there was no space left and so the new Metropolitan southbound tunnel had to instead go under the properties on the east side of Finchley Road.

The North Star, under which the Met’s southbound tunnel runs. Finchley Road station’s in the distance.
This new section of tunnel for the Met had to be built fifty feet east of the old tunnels under Charles House, the adjacent Nat West bank and the North Star inn before passing below the nearby petrol station forecourt and then back underneath Finchley Road. The structure is very close to the surface and a reason why one probably wont see any buildings erected where the petrol station is sited (picture below) because very expensive underpinning would be required.

The Met runs under this road and service station forecourt before coming back under Finchley Road.
It is said fifteen hundred men were employed on the new LTPB works between Baker Street and Finchley Road. The finance for this came from the Government’s new works programme 1935-1940.

The tunnels at Finchley Road before demolition to make way for the Bakerloo.
The reason for these new tunnels being built so close to the surface was not because they wanted it as such, but rather that the original Swiss Cottage line rose on a gradient in readiness for the extension to Hampstead. The lie of the land the other way towards Finchley Road was the problem. There was simply no way to dig these tunnels any deeper without incurring a penalty of severe and quite possibly dangerous line gradients.
The large department store (just outside Finchley Road station) which was once a branch of Habitat and now houses the Waitrose store was built in the mid 1930’s,just before the new tunnel works. The store had to be considerably underpinned to enable construction of the new northbound Met tunnel.
Additionally a huge girder bridge 110 feet long with 21 spans (a covered way as some would describe) had to be built south of the station in order to accommodate the new tunnels and the ramps to the new tube tunnels, and also form the foundation for a much widened Finchley Road.
The merge between the old and new tunnels north of Swiss Cottage does show the original tunnel to Hampstead was built much further than anyone thought. This point at which the tunnels meet is the summit of the line between Baker Street and Finchley Road. According to TfL this location is 2850 meters from Baker Street and 350 metres from Finchley Road.

The old tunnel for the aborted line to Hampstead – seen from a southbound train.
Its not easy to see the tunnel in question, however observers can spot it just before the derelict Swiss Cottage station. Its announced by the train turning into a right hand curve where in an instant the old tunnel flashes past. Its obscured in part by cables and infrastructure. It seems the old tunnel itself has been propped up by supports or some sort of underpinning as a shopping parade has been built above.
The recent improvements track works over the past few years that have taken place between Baker Street and Finchley Road may well impress others to think the problems of the tunnels north of Baker Street are over for a good while. Perhaps this is so however its not that long since considerable works were undertaken to stablise the tunnels.
That occurred in the late 1950s when a considerable stretch of the tunnels at Swiss Cottage had to have the old concrete invert replaced. The tunnels have a long history of structural problems due to regular water ingress from the roads above, including burst water mains, and although the current works will improve things considerably, their problems are by no means over.