After the nationalisation of British Railways in 1948, Marylebone was initially kept open as a long-distance station.
New services were introduced, including the Master Cutler service to Sheffield and the South Yorkshireman to Bradford, but they were not well-used.
From 1949, all local services towards High Wycombe and Princes Risborough were routed into Marylebone, although the frequency of trains was reduced two years later.

The Great Central Main Line duplicated the route of the Midland Main Line and long-distance trains from Marylebone were scaled back from 1958, leading to the closure of the Great Central Main Line north of Aylesbury on 4 September 1966 in the Beeching Axe.

The rundown of services began after the line was transferred from British Railways' Eastern Region to the London Midland Region, although the station and the first few miles of its route had been part of the Western Region from 1950.
In 1958, the Master Cutler was diverted to London King's Cross and the East Coast Main Line.
In 1960 all express services were discontinued, followed by freight in 1965.
From then until closure, only a few daily long-distance "semi-fast" services to Nottingham remained.
Marylebone's large goods yard was closed and sold to the Greater London Council for housing.
The last long-distance service ran on 4 September 1966, except for a brief reprieve the following year when Paddington was undergoing signal works.

Marylebone was then the terminus for local services to Aylesbury and High Wycombe only, with some services extended to Banbury.
They were switched to diesel multiple unit (DMU) operation following the phasing out of steam.
British Rail Class 115 DMUs were introduced to local services in 1962.
The station was transferred from the Western Region to the London Midland Region in 1973.
The Great Central Railway's long-distance connection from Marylebone via High Wycombe, was closed the same year.
After the nationalisation of British Railways in 1948, Marylebone was initially kept open as a long-distance station. New services were introduced, including the Master Cutler service to Sheffield and the South Yorkshireman to Bradford, but they were not well-used. From 1949, all local services towards High Wycombe and Princes Risborough were routed into Marylebone, although the frequency of trains was reduced two years later.
The Great Central Main Line duplicated the route of the Midland Main Line and long-distance trains from Marylebone were scaled back from 1958, leading to the closure of the Great Central Main Line north of Aylesbury on 4 September 1966 in the Beeching Axe. 
The rundown of services began after the line was transferred from British Railways' Eastern Region to the London Midland Region, although the station and the first few miles of its route had been part of the Western Region from 1950. In 1958, the Master Cutler was diverted to London King's Cross and the East Coast Main Line. In 1960 all express services were discontinued, followed by freight in 1965. From then until closure, only a few daily long-distance "semi-fast" services to Nottingham remained. Marylebone's large goods yard was closed and sold to the Greater London Council for housing. The last long-distance service ran on 4 September 1966, except for a brief reprieve the following year when Paddington was undergoing signal works.
Marylebone was then the terminus for local services to Aylesbury and High Wycombe only, with some services extended to Banbury. They were switched to diesel multiple unit (DMU) operation following the phasing out of steam. British Rail Class 115 DMUs were introduced to local services in 1962. The station was transferred from the Western Region to the London Midland Region in 1973. The Great Central Railway's long-distance connection from Marylebone via High Wycombe, was closed the same year.
Marylebone station