But there is a long way to go before Tube users speed across the heart of London in swish air-conditioned trains.
Although Darling supported Crossrail on principle he also provided a track full of caveats. Crossrail will have to go through a minimum of four consultative and legislative stages before it gets the go ahead. These include a public consultation in the Autumn and further consultation on methods of raising money for the scheme.
The latter is where Crossrail could hit the buffers. The amount needed to be raised by the private sector is high - up to £7.5bn - and if the figure is not forthcoming the government won't commit its £2.5bn share of the funding.
No doubt the Treasury wants to avoid the cost-overruns experienced at Holyrood and Gordon Brown will be carefully assessing the exact cost of the scheme bofore giving it the green light.
Arup's private Crossrail consortium has indicated how some of the private money might be raised. It has said that it could build a core route with no public finance but secured against fare revenue and incremental property values.
The results of the consultations and studies will feed into a hybrid bill in 2004/05, which will also include input from Cross London Rail Links (CLRL), the group responsible for overseeing the project. It's predicted that the bill will then take another three years before it completes its passage through parliament.
This will almost certainly mean that Crossrail won't be built in time for the potential 2012 Stratford Olympics. The delay has dismayed Ken Livingstone. He told Darling to "get up of his arse" to make sure the Crossrail link was completed in time for a Olympics.
Some commentators believe that the CLRL have had enough time and money - £300m - to have already completed a feasibility study. Livingston said that the transport department where the CLRL resides is guilty of "timewasting and prevarication."
The next ten years will determine whether the country really has the political will to turn the creaking Tube system into a network worthy of the City it serves.