Office of Rail Regulation: 'More efficiency needed'
Network Rail has been told by the rail regulator that it must find savings of £2bn over the next five years at the same time as improving punctuality.
But the Office of Rail Regulation (ORR) said the cost cuts would not come at the expense of safety.
Anna Walker from the ORR told the BBC: "We must have the improvements... but it must be done more efficiently."