National Rail has stated that a 'good service' is expected to return by 12pm today following major disruption this morning.
Passengers were previously told to travel only if necessary as a fault with the signalling system at Leighton Buzzard caused various cancellations and delays.
National Rail previously said that disruption could last until the end of the day but has now announced that train services should be back to normal by 12pm.
"Lines have now reopened, however trains may still be disrupted as services return to normal," a spokesperson said.
In the mean time people travelling between Hemel Hempstead and Milton Keynes Central should expect that services "will be subject to major disruption and potentially very busy so allow plenty of extra time when using them".