The Department for Transport is determined to limit its contribution to £170m with all future cost rises paid for locally.
Cllr Peter Millea, Liverpool's executive member for regeneration, made a passionate speech in support of the tram at Monday's group meeting, helping swing support behind it.
Last night, he said: "It is still fingers crossed but the ball is now firmly in the Government's court.
"We have shown we meant what we said all along and that is we want this project to go ahead." A total of 3,000 tonnes of grooved rails will be laid on the 11-mile route of Line One from Kings Dock to Kirkby.
Merseytravel chief executive Neil Scales paid £245,000 for the first 1,000 tonnes and a second is already on the way to the M-Pact depot.
Buying the steel early, before the scheme will definitely go ahead, is a calculated gamble because of the insatiable demand for steel from the Chinese marketplace which has seen the price of steel steadily rise.