Chiltern Main Line
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The Chiltern Main Line is an inter-city and commuter railway in the United Kingdom, part of the British railway system. It links London and Birmingham on a 106 mile route which runs via North West London, Buckinghamshire, Oxfordshire and Warwickshire.
The line complements the West Coast Main Line by providing an additional inter-city link between England's two largest cities, as well providing commuter services between London and Buckinghamshire and beyond.
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[edit] Passenger Services
Passenger services on the route are currently operated by Chiltern Railways. Some services between Birmingham Snow Hill and Leamington Spa are operated by London Midland, whilst CrossCountry run services over the line between Birmingham New Street and Coventry to Banbury as part of their services from Scotland and the north of England to the south coast of England.
[edit] Line Speeds
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[edit] Marylebone to Neasden
After departing Marylebone, the speed limit rises to 50mph for Sprinter-class multiple unit trains (of which the Class 165s and Class 168s are qualifying derivatives) and 30mph for all other types of train. Beyond Canfield Place, near Finchley Road, the line speed remains at 30/50 until a point near Willesden Green, where the line speed for Sprinter-class trains rises to 60mph. The line speed remains 30/60 as far as Neasden Junction, where the Chiltern main line splits from the line to Aylesbury.
[edit] Neasden to Northolt
This segment has a speed limit of 60mph.
[edit] Northolt to High Wycombe
Beyond Northolt Junction, the line speed rises to 75mph for Sprinter-class multiple unit trains and 60mph for all other types of train. This speed is maintained throughout the entire section, with slacks in at least two places:
- Gerrards Cross, where the speed for non-Sprinter trains drops to 35mph in both directions (speeds for Sprinter-class trains passing the station remain at 75mph).
- Beaconsfield, where the speed for non-Sprinter trains drops to 55mph in both directions (the speeds for Sprinters also remain at 75mph).
At High Wycombe, the heavily curved right-of-way used by the line (an artifiact of its historical roots as a branch from Maidenhead) requires a severe drop in speeds; the speed through the station is 25mph for all types of train.
[edit] High Wycombe to Princes Risborough
North of High Wycombe, speeds remain low as the line curves through the northwestern suburbs, passing the site of West Wycombe railway station. Beyond this point, the line straightens significantly (as a result of its upgrade by the GWR in the early 1900s); the speed limit increases to 75mph for all types of train.
North of Saunderton, the speed limit drops to 60mph on both roads; the speed limit is difficult to reach on the down side due to a steep 1 in 88 rising gradient. Just to the south of Princes Risborough, the line speed drops to 40mph for all types of train and remains this speed through the station limits; just north of the station, line speeds for Sprinters rise to 65mph. Further north, line speeds rise even further, to 100mph for Sprinter-class trains (reachable only by the Class 168s) and 60mph for all other types of train.
[edit] Princes Risborough to Aynho Junction
Line speeds remain 60/100 north of Risborough in the appropriate directions; speed limits are lower when trains are running in the wrong direction on either track. At Aynho Junction, train speeds are low on the down side, but higher on the up side.
[edit] Aynho Junction to Leamington Spa
Beyond Aynho Junction, line speeds rise to 90mph for all types of train and remain 90 throughout this segment, with a slack through Banbury.
[edit] History
[edit] Early history
The original line from Birmingham, England to London, England was built by the Great Western Railway (GWR) in the 1850s, to connect Oxford to Birmingham and Wolverhampton. For many years, trains from Birmingham to London went the "long way round", via Leamington, Oxford and Didcot, then along the Great Western Main Line to London Paddington. This routing was circuitous, and not competitive with the LWNR's London-Birmingham route; such routes between major conurbations were common in the early days of the GWR, earning it the sobriquet "Great Way Round".
In this time period, the only segments of the Chiltern Main Line that currently existed were the Aynho-Banbury-Leamington-Birmingham routing, and the single-track Wycombe Railway between Princes Risborough and High Wycombe; this single-track line continued further south, via Bourne End, to Maidenhead on the 1838 Great Western Main Line.
[edit] GW/GC Joint Line
In an attempt to compete with the LNWR's London-Birmingham route, the GWR took advantage of an existing partnership with the Great Central Railway (GCR) to build a new, direct route referred to as the Great Western and Great Central Joint Railway (the two companies were already working together over a link between Woodford Halse station and Banbury).
The new route started at Northolt Junction in Middlesex, from which two lines ran southward:
- a direct line, referred to as the New North Main Line, towards London Paddington via Greenford and Old Oak Common, built by the GWR. This line also included a triangular junction at Greenford, providing access to the 1838 Great Western Main Line via Castle Bar Park.
- a line via South Harrow and Wembley to meet the existing GCR route at Neasden Junction, near Neasden station on the Jubilee Line. This is the line used by almost all Chiltern services.
The new route ran northwest via Gerrards Cross to High Wycombe, where the line met the existing route of the Wycombe Railway's single-track branch from Maidenhead. North of High Wycombe station the existing route was reused, with significant upgrading of the formation, and a new route chosen for the up line north of Saunderton. The existing route, taken by the down line today, has a gradient of 1 in 88, which was too steep for the heavy coal trains run by the GCR. As a result, the two tracks of the route are horizontally and vertically separated at this point, with the down line crossing the Chiltern Hills at the Risborough gap and the up line passing through an 88 yard tunnel on a flatter gradient.
Upon reaching Princes Risborough, new construction was started again. The station was already a major junction, with the single-track line bifurcating into three branches; one to Watlington and Chinnor (which survives in part as the Chinnor and Princes Risborough Railway), one to Thame and Oxford, and one to Aylesbury. The new main line was constructed in the 'V' formed by the three branches, and ran northwest to a point near the hamlet of Dorton, where the line curved to the north to meet the GCR's main line at Grendon Underwood Junction in Buckinghamshire.
The line was completed in its entirety in 1906 (with portions opening as they were completed), and immediately benefited both parties. The GCR, unable to gain equal access to their route via Aylesbury, Amersham and Harrow, gained a new and fast bypass route for their express passenger and freight services to London Marylebone, while the GWR gained a fast cut-off that allowed their Birmingham trains to run via Gerrards Cross, Princes Risborough and Oxford to regain their original routing.
[edit] The Bicester cut-off
Four years later, the GWR constructed a second line, starting at Ashendon Junction in Buckinghamshire, near Dorton, and running northwest via Bicester to meet the existing route from Oxford at Aynho Junction. This truncated the original Joint Line to Ashendon Junction, the section northwards of there being sold to the GCR after the completion of the Bicester cut-off. The new cut-off provided both a faster route between London Paddington and Birmingham Snow Hill stations for the GWR, which could now divert its services to the latter station away from the route via Oxford; the final saving in distance was approximately 20 miles.
[edit] Heyday, decline and resurrection
During the heyday of the route, many prestigious trains ran from Paddington to the northwest of England via the Joint Line, reaching Wolverhampton, Chester, Liverpool and Birkenhead. Various through services from Marylebone to the GCR network also ran via the Joint Line.
In the 1960s, when the rival West Coast Main Line (WCML) was electrified, express services from London to Birmingham on this route were discontinued as part of the Beeching Axe; beforehand, it was even more heavily used by many long trains running from Liverpool and Birkenhead, as the WCML was restricted in capacity due to the electrification works. All local trains on the route were diverted to Marylebone in 1963, and Greenford station on the New North route between Old Oak Common and Northolt Junction was run down and eventually closed. The route was downgraded to secondary status in 1967, and subsequently single-tracked between Princes Risborough and Aynho Junction, which remained a flying junction. Snow Hill station in Birmingham was also closed, along with the line to Wolverhampton.
The route was eventually considered for partial closure in the 1980s, with all services returning to Paddington via the New North route, and Marylebone station and all lines leading to it being closed - services to and from Aylesbury would have run via Princes Risborough. Marylebone was formally reprieved in 1986, however, and the closure proposals were rescinded.
Services were expanded somewhat in the late 1980s, when Snow Hill station was re-opened, although they still ran from Marylebone rather than Paddington. In the early 1990s, the New North route between Old Oak Common and Northolt Junction was singled between Old Oak Common and Park Royal and also between Greenford and Northolt Junction. The Total Route Modernisation performed by BR in the early 1990s removed most of the vestigial traces of main line heritage from the route, downgrading it purely to a commuter line with a minimum of available infrastructure; until that point, High Wycombe station alone had retained almost all of its original track layout, the other major stations on the line having already been downgraded. In 1992, the old signal box at Aynho Junction was closed and replaced with modern signalling controlled from Banbury South signal box; the structure stood until 2002, when it was demolished. As part of these renovations, BR also installed the advanced Automatic Train Protection (ATP) system mainly as a trial with a view to rolling it out nationwide. However, privatisation intervened, and the Great Western Main Line was the only other line to be equipped with ATP.
[edit] Chiltern Main Line
Upon rail privatisation in the 1990s Chiltern Railways took over the route, and in 1998, the line between Princes Risborough and Bicester North was redoubled by the company. This included the total reconstruction of Haddenham and Thame Parkway station at platform level, with two side platforms instead of the single platform constructed in 1987. In 2002, after Chiltern won their 20-year franchise, the line between Bicester North and Aynho Junction was also redoubled.
Part of the old Great Western route from Birmingham Snow Hill to Wolverhampton is now used by the Midland Metro light rail system.
The line from Northolt Junction to Paddington alone has not been improved, and only one Chiltern train a day from Princes Risborough, and back, uses it, and only during the week (except on Wednesdays). Freight trains carrying refuse from London use the line, however, and it has been used as a diversion when work is taking place on the line to Marylebone, or when the normal line into Paddington is closed. HSTs are often sent around the Greenford loop via Ealing Broadway and Park Royal to turn them around for operational reasons.
As of September 2006, Chiltern has completed their Evergreen 2 upgrade project. The project, which was carried out by Carillion, realigned the track through Beaconsfield to increase non-stop speeds from 40mph to 75mph, installed additional signals between High Wycombe and Bicester North (as well as between Princes Risborough and Aylesbury), and added two new platforms to Marylebone. The new platforms are on the site of the old daytime carriage sidings, which were replaced with the new Wembley Light Maintenance Depot, just to the south and west of Wembley Stadium station. The new platforms and partial resignalling of the station throat now make it possible to run 20 trains per hour in and out of the station.
[edit] Future
There are several plans for this route; [1] [2]
- The restoration of the quadruple track between South Ruislip and West Ruislip, allowing trains to call at both stations without blocking the line. Triple track currently exists at West Ruislip, with the up platform loop still in situ, and at South Ruislip, with the Down Main through line also in situ. This would involve the reconstruction of the down platform at West Ruislip, the reconstruction of the up platform at South Ruislip, and the demolition of West Ruislip signal box.
- Building of the West Hampstead Interchange to allow easy interchange with the Silverlink Metro, Jubilee line, Metropolitan Line and Thameslink line. This would give Chiltern Railways an interchange with the future Orbirail line.
- A new railway built between Oxford and Princes Risborough, this would then give Oxford an alternative to the Oxford-Paddington route. The Oxford to Banbury spur would then be handed over to the Chiltern mainline to create a diversionary loop from Princes Risborough to Banbury via Oxford. This option requires an expensive crossing of the M40 motorway.
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![[1]](http://www.cwn.org.uk/business/a-z/c/chiltern-railways/images/train-route.gif){kind=link}