The Central Line has a 'shortage of trains'. Most days, customers are having to wait ages for trains that arrive already packed with passengers. LU's explanation for the missing trains is that the motors are failing 'at a higher rate than was expected', which means that fleet engineers are having to work 'day and night' to fix the problem. But even LU admits that there is 'no quick fix' and that 'we are likely to see a shortage of trains for some weeks to come'.
The underlying cause must be that the Central Line trains are old, dating back to 1992. They are also tired out from running an ever more frequent train service. The issues that result in exhaustion for drivers on the Central Line -short turnarounds, lots of time spent driving - are also causing Central Line trains to demand a rest!