Labour party members have called on Ed Miliband to put the railways and postal service back into public hands if the party wins power at the next election.

Delegates voted unanimously on Wednesday to renationalise Britain's train operations and reverse the coalition's decision to sell off a majority stake in Royal Mail at the party's autumn conference.

They also called on Labour to campaign against creeping privatisation in the NHS, arguing the current "harmful, market-led approach" should be replaced by a system driven by "care, not competition".

The votes come the day after rightwing newspapers interpreted the Labour leader's speech as a return to "Red Ed" Miliband over his plans to freeze energy prices for almost two years and force developers to free-up land for housebuilding.

However, senior Labour sources made it clear the party was not in favour of renationalisation, signalling that the leadership was prepared to ignore the motions in its election manifesto.

Labour opposes the coalition's plans for floating most of Royal Mail on the stock market, and Ian Murray, the shadow postal affairs minister, is attempting a last-minute bid to halt the privatisation with a vote in parliament.

However, the party would not want to commit vast amounts of cash to buying the postal service back once the sale has happened, one senior source said.

The party is exploring different modes of rail ownership, such as the non-profit operation of the east coast mainline, but is not in favour of a wholesale return to nationalisation, he added.

"Renationalisation is not our policy," the senior Labour source said. "Conference is entitled to its view but we are going to do the right thing. We are not going to spend money we do not have."

Labour conference voted for a similar motion to nationalise the railways in 2004 and that never made its way into the party's 2005 election manifesto.

During the impassioned debate, Mick Carney, president of the Transport Salaried Staff Association, condemned the current rail system for failing to protect passenger safety and causing delays and cancellations,

"Conference calls on a future Labour government to run our railways in the interest of passengers by retaining and extending this successful model of public ownership to each franchise as it expires and by integrating track and train operations," he said. "The billions that this will save must be used to invest in our rail network and to cut fares for hard-pressed passengers."

He was backed by Tosh McDonald, the vice president of the union Aslef (Associated Society of Locomotive Engineers and Firemen), who said Labour should not be afraid to talk about the ideology of public ownership.

Another motion moved by the Communication Workers Union (CWU) said privatisation "will jeopardise the contribution Royal Mail makes to the national economy through the universal service obligation".

It added: "Conference agrees an incoming Labour government should renationalise Royal Mail in the event of the coalition government actually selling the company."

Members voted in favour of both the motions by a show of hands, as well as condemning the coalition's lobbying bill as a cynical attack on the trade unions.

Billy Hayes, general secretary of the CWU, said he was delighted with the vote to renationalise Royal Mail if it has been sold by the current government.

"Labour's conference decision should raise a warning flag for potential investors," Hayes said. "Poll after poll has shown public opposition to the sale, and with the company making substantial profits, there is no economic argument for the sale."