The Prime Minister, Julia Gillard, stood beside the Premier, Kristina Keneally, and promised $2.1billion towards the $2.6billion Parramatta to Epping Rail Link from 2014.

By that afternoon, the first trickle, then a flood, of reaction followed.

In the Hills, the federal and state Liberal MPs and Hills councillors, including mayor Peter Dimbrowsky, cautiously welcomed the news but questioned whether it would actually happen, given the project's history.

Mitchell MP Alex Hawke said he was ``tired of the cynical spin'' and that the announcement was ``not believable''.

Mr Hawke said the ``real scandal'' was a lack of expenditure in Sydney from the billions of dollars of federal infrastructure funding.

Cr Dimbrowsky said he hoped it wasn't going to be just another disappointment.

By Monday, the Coalition leader, Tony Abbott, had written it off, saying voters would see it as just ``another empty Labor promise''.

Pointing to the irony of a federal Labor Government announcing funding for the Parramatta to Epping Rail Link, that had been promised and then axed by successive state Labor governments, Cr Andrew Jefferies also expressed doubts that it would happen.

``You have to question the timing of the announcement [on the eve of the federal election] but it must be a firm commitment,'' he said.

The local MPs were all unanimous in suggesting the North West Rail Link, which won't be operating until 2024 under the present proposal instead of this year under an earlier plan, was the more obvious priority in bridging the region's transport gaps.

The state MP for Castle Hill, Michael Richardson, and for Hawkesbury, Ray Williams, both said Labor had its priorities wrong.

``The North West Rail Link should come first,'' Mr Richardson said.

Mr Williams said the announcement was ``taking the cheap option to make it look like they are doing some infrastructure work''.

``With the current completion date of the North West Rail Link of 2024, Captain Kirk and the Starship Enterprise couldn't find it,'' Mr Williams said.