TUBE infrastructure company Metronet, which maintains two-thirds of the London Underground, plans to cut 300 jobs.
Metronet said it would ask volunteers to come forward and take voluntary redundancy and pledged there would be no compulsory lay-offs.
The losses will be mainly among administration and back office staff, although 10 operational posts will be axed.
Metronet employs 5,000 staff and the restructuring is designed to align its two separate Tube businesses.
Metronet Rail BCV maintains the deep line Bakerloo, Central, Victoria and Waterloo and City lines and Metronet Rail SSL controls the sub-surface lines including the District, Circle, Metropolitan, East London and Hammersmith and City lines.
A spokesman said the changes had the approval of London Underground.