Spiking Tory guns as she opened a debate on the sale of Railtrack, Labour's transport spokeswoman said she would "like to say a word on tax".
But, to cheers from her colleagues, she went on: "The cost of privatising the railways amounts to an extra pounds 106.38 for every taxpayer in the country. This is equal to an extra 1p on the basic rate of income tax."
Ms Short had been expected to come under attack from MPs hoping to exploit her weekend remarks.
However, most Conservatives gave the debate a miss and only came into the chamber for the division.
Despite speculation of a cliffhanger vote, the Labour motion calling for withdrawal of the flotation plan was defeated by 306 to 287.
There were only 14 Tory backbenchers in the chamber when Sir George Young, the Secretary of State for Transport, rose to speak - compared with some 30 on the Labour side - and no telling blows were landed.
Sir George wondered if the higher levels of rail investment Ms Short talked of were going to come from higher taxes on MPs, who she had seemed to imply could afford to pay more.
"One can but contrast the way the leadership embraced and protected Harriet Harman sending her son to a grammar school, and silenced Ms Short for suggesting that the better-off should pay more taxes.
"The one is endorsed for acting like a Tory; the other rebuked for speaking like a socialist," Sir George said.
In a stern message to would-be shareholders, Ms Short said that a Labour government could take power to direct Railtrack's investment, control charges on train operators, restrict land disposals and also claw back most of the company's income from property sales.
"The use of regulation to protect the national interest will change the likely rate of return to shareholders," Ms Short warned. A preliminary prospectus for the pounds 1.8bn sale was published on Monday.
Ms Short said Labour wanted to be straight with potential investors. In government it would use all the levers at its disposal to reintegrate the railways and mobilise a public-private partnership to secure an increase in passengers and freight.
"To place our hands directly and securely on those powerful levers of control we shall need only a small amendment to the Railways Act of 1993."
Sir George said Labour's attempts to stop the privatisation would not work. One million prospective investors had already registered with share shops and by the time of the general election there would not be much, if anything, left of BR to reconstitute.
But as the Secretary of State waxed eloquent about benefits such as bus links introduced by South West Trains and on-board check-in facilities on the Gatwick Express, a deflationary note was introduced by David Chidgey of the Liberal Democrats.
Mr Chidgey, MP for Eastleigh, said the 8.50pm on Tuesday from Waterloo to Poole, "was unfortunately mistakenly signalled on to the Salisbury line.
"You don't have to be a railway buff to know that the line from Waterloo to Weymouth, through Poole, is electrified. The line to Salisbury is not. Consequently, it ground to a halt just west of Basingstoke, where the staff on the train led passengers to safety by torchlight.
"Is this the new modern railway Sir George talking of?"Reuse content