Services are suspended completely on the Hammersmith & City and Circle Lines and partially suspended on the District line as drivers are refusing to drive trains due to concerns about the emergency braking.
Trains stopped running on the District Line between High Street Kensington and Edgware Road from 1740 BST on Wednesday.
And services were suspended on the Circle and Hammersmith & City Lines at 1910 BST and 1940 BST respectively.
A TfL spokeswoman said: "Local trade union safety representatives have raised concerns about the design of the traction brake controller on the C stock trains used on these lines.
"As always, we are addressing the safety concerns of the trade unions.
"However, these trains have been in safe operation for over 25 years, and there is no reason for the service to the public to be disrupted whilst we seek to address the issues raised."
There's been no comment as yet from Aslef and the RMT. However keep an eye on Tube's site and good luck if you're using any of those lines this morning.