WASHINGTON (AP) — A bipartisan coalition on the Senate Appropriations Committee moved Thursday to roll back House GOP-backed cuts to Amtrak, transportation projects and affordable housing projects, but pressures elsewhere in the budget may make the funding levels unsustainable as the massive $108 billion spending bill moves ahead.

The transportation and housing bill was targeted by House Republicans for $1.8 billion in cuts relative to current program levels; the Senate measure is about $2.4 billion above the House measure and more than $600 million above current spending.

The additional money — made available through bookkeeping maneuvers by Senate panel chair Barbara Mikulski, D-Md. — maintains funding for a $550 million transportation grant program that dates to President Barack Obama's 2009 stimulus bill, additional funding for rent vouchers for the poor, and allows for new resources to address the risks of shipping crude oil by rail.

A second, $51 billion bill funding the Commerce and Justice departments and space and science programs also came in above Obama's budget request, including a new program to ease a backlog of untested rape kits and improve the way law enforcement treats sexual assault victims. Additional money for NASA would keep development of a new heavy lift launch vehicle on track for a 2017 launch date.

The bills are the third and fourth of the 12 annual measures that fund the day-to-day budgets of federal agencies for the budget year beginning Oct. 1. Mikulski is trying to get the appropriations process back on track and is working hard to get Republican support for the measures.

The annual spending bills give lawmakers and interest groups opportunities for making policy that they are otherwise denied because of Congress' chronic gridlock.

On Thursday, for instance, the trucking lobby scored a major win with passage of an amendment by Sen. Susan Collins, R-Maine, to suspend some government restrictions on the hours that truckers may drive. The measure, approved by a bipartisan 21-9 vote, would block a rule that requires drivers who take a 34-hour break before starting a new 60-hour workweek to include the hours between 1 a.m. and 5 a.m. on two consecutive nights.

Collins said the rule is pushing more truckers off the roads during overnight hours, when traffic is lightest, and is therefore causing more congestion and accidents.

"It's much safer to have these trucks on the road during nighttime hours," Collins said.

Another provision pushed by Collins and the industry would lift a limit on how frequently drivers can take advantage of the 34-hour break that permits them to start another long workweek. The Transportation Department would be required to study the effect easing the restart rules would have on driver safety.

Collins said she had rejected requests to lead a more sweeping attack on the hours of service rules, which include a mandatory 30-minute break during a 14-hour on-duty period, 11-hour drive-time limits and 10 hours of rest between shifts. The rules took effect last July.

The underlying bills earned bipartisan praise. The panel's top Republican, Sen. Richard Shelby of Alabama, emerged pleased with funding for development of a new rocket at a major NASA facility in Huntsville, Alabama. Susan Collins, R-Maine, praised funding for "much-needed investments in our nation's transportation network" like so-called TIGER Grants awarded for major transportation projects.

But the relatively small increases allowed by the Senate measures are possible because Mikulski is using accounting tricks to create more headroom under tight spending "caps" imposed by a December budget pact between House and Senate Budget Committee chairmen Rep. Paul Ryan, R-Wis., and Sen. Patty Murray, D-Wash. They include padding war accounts and declaring more than $1 billion for battling western wildfires exempt from the spending cap.

Republicans oppose Mikulski's bookkeeping moves, and the cuts are likely to be at least partially restored in negotiations with the GOP House later this year.