Shadow transport minister Bernard Jenkin said that the UK rail system was "made into too many different companies".
He said the railway was "ripped apart at privatisation" and the resulting structure was designed to maximise the proceeds to the Treasury, not safety or investment.
He reiterated his position on BBC Radio 4 on Friday, saying the two big problems facing the railways were "the years and years of under-investment and the fragmentation created at privatisation" plus a 25% increase in the number of trains".
Asked whether fewer companies would improve matters, he said: "I think it would help."
Responding to Mr Corbett's position, Mr Jenkin said: "I agree wholeheartedly with Gerald's comments that we need a change in the way the railway is run."
Industry needs support
Mr Jenkin stressed that no-one wanted to "turn the clock back" and he argued that the industry needed more government support, suggesting that the rail regulator was now "adversarial and legalistic".
"If you can give the industry confidence, if you can give employees confidence in their employers and you can give the city confidence in the businesses then it will be able to raise far more investment," he said.
However, former transport minister Peter Bottomley defended the privatisation.
He said there had been a cut in the number of deaths, train use had increased and capital investment was growing fast.
"These crashes are unacceptable, but the overall picture is one of benefits to passengers, benefits to railways, fewer people on the roads and fewer deaths," he said.
Tuesday's disaster at Hatfield, in which four people died and 35 were hurt, was the third major rail crash in three years.
Together with train operators, Railtrack has agreed that the focus for the immediate future must be "safety, maintenance and investment".
But it warned there will be a price to pay, with major disuption to passengers as emergency engineering work is carried out.