He has come under pressure from former deputy prime minister Lord Prescott and more than 30 would-be Labour MPs to commit to renationalisation, but Mr Miliband said Labour would not return to the old days of British Rail, although the current system was flawed.
He has been urged to consider the success of East Coast since it was taken back into public ownership, with Lord Prescott suggesting the existing franchise deals should simply be allowed to lapse.
The Labour leader told BBC1's Andrew Marr Show: "We are looking at all the options on the railways. We are not going to go back to old-style British Rail."
He said Labour would be "pragmatic" and "we have got to recognise that the system at the moment has flaws in it".
"Passengers are paying high fares in this country and we are paying big subsidies from the taxpayer."
East Coast was in public hands, but the Government was "dogmatically" privatising it, he said.
"I want to see value for money for the taxpayer. I'm never going to write a blank cheque and I am not going back to the past, but we are looking at different options.
"There is a balance to be struck here because there are some benefits you can have sometimes from competition and we are not gong back to the old monolithic model that was British Rail.But we do need to look at how we can have a coherent system."
The renationalisation call from parliamentary candidates came in a letter to a Sunday newspaper.
They said: "Train companies walk away with hun-dreds of millions of pounds every year, despite running monopoly services and benefiting from £4 billion of public investment in the rail network every year."
The added: "The not-for-private-profit model that works so well on the East Coast line has shown how there is a better way to run Britain's rail services."