Crossings on the Sunbury, Frankston, Ringwood, Cranbourne and Pakenham lines have been put at the front of the funding queue in the government's $5-$6 billion level crossing removal program, with $2.4 billion committed over the next four years in Tuesday's budget.

But busy crossings on the overcrowded Werribee and Craigieburn lines - both of which run through Labor heartland - look likely to stay in place until after the next election.

And another key Labor promise – the $400-$600 million Mernda rail extension – is off to a slow start, with just $9 million for planning locked in in this budget.

The Andrews government's first budget contained few other public transport surprises, because most of the big-ticket items had already been revealed in recent days.

There is $1.5 billion for the $9-$11 billion Melbourne Metro rail tunnel,  but $840 million of that has been deferred until 2018-19, the year construction is planned to start.

Commuters on overcrowded peak-hour trains should not expect much short-term relief from the crush, despite the $2 billion commitment to buy new trains and trams.

Less than a quarter of the $1.3 billion committed to buy 37 new high-capacity metropolitan trains is in the forward estimates to 2018-19, and half of that money is four years away from being spent. The budget papers state the project "will be procured as a public-private partnership".

But then public transport patronage was flat in 2014-15, with Metro train trips barely increasing from 225.7 million to 227.7 million journeys, more than 25 million fewer than the growth that was predicted last year.

The government attributed the negligible increase in patronage to "current economic conditions and [the] impact of historically low petrol prices on discretionary off-peak travel".

Tram patronage was equally flat, rising from 176.4 million journeys to 178 million, while the number of bus trips taken barely moved, from 124.7 million journeys to 125.8 million.

Elsewhere in the budget, $360 million was committed to upgrading signalling on the Cranbourne-Pakenham rail corridor and $55.6 million went to a trial of next-generation high-capacity signalling on the Sandringham line. If successful, the technology could enable trains to run just two minutes apart, greatly boosting capacity across the rail network.

The government has committed $15 million to extending and reinstating bus routes, and a new $5 million bus interchange will be built at Huntingdale, an important destination for Monash University students and staff that has long suffered from poor train-bus connectivity.

Taxi licence holders will be able to claim from a $4 million hardship fund for those most heavily disadvantaged by the former Coalition government's industry overhaul.

Meanwhile, the budget papers reveal that the total cost of the Regional Rail Line project - a 45-kilometre rail link for V/Line trains between West Werribee and Southern Cross Station due to open in June - has fallen from $4.1 billion to $3.65 billion.