Network Rail Director Mick Carne said the planned £38 billion upgrade to Britain's railways will improve the resilience of the system and the service for passengers.
Speaking to Consumer Editor Chris Choi he said the investment announced today was vital, and that he was "very conscious of the fact" that Network Rail "had a better job to do".
The head of one of the train drivers' trade union has hit out at the Government's strategy for improving the railways and called for the network to be returned to public ownership.
Mick Whelan, the general secretary of Aslef, said the £38bn announced for 2014-19 "only keeps us standing still".
The truth is that, after 20 years of privatisation, things aren't getting better. That's why opinion poll after opinion poll shows that most people - including most Conservative voters - in this country want our fragmented railways brought back into public ownership so we can run a properly integrated public service. It's time to build a better railway for everyone in Britain.
The £38 billion revamp to Britain's railways is "a bold plan" but one "customers expect and want to see", the head of Network Rail has told Daybreak.
Mick Carne explained: "We are going to spend about £13bn in the operating and maintenance of the railway, but about £25bn on really making substantial improvements to the railway."
Britain's railways will get a £38bn investment as part of a massive revamp plan designed to tackle growing demand, Network Rail is expected to announce later today.
Plans are expected to include electrification of 850 miles of track from Maidenhead to Swansea and Sheffield to Bedford, as well introducing a 24 hour service to the Thameslink programme.
On top of that, £13bn will be poured into replacing and renewing older parts of the network, such as refurbishing nearly 6,000 sets of points.
Hundreds of stations across the country will be transformed including major schemes at London Bridge, Manchester Victoria, Birmingham New Street and Glasgow Queen Street.
Transport Secretary Patrick McLoughlin said: “A key part of this government’s long term economic plan is investing in world class infrastructure."
However, Network Rail is also braced for a hefty £70m fine from regulators after failing to hit its target for train punctuality.