WASHINGTON, June 17 (Reuters) - U.S. Senate Majority Leader Chuck Schumer on Thursday met with members of a bipartisan group of senators struggling to develop an infrastructure proposal that could make it through Congress while achieving President Joe Biden"s goals. Twenty-one of the 100 senators, including 11 Republicans, nine Democrats and one independent who caucuses with Democrats have joined on the bipartisan proposal, building out a framework that sources said would cost $1.2 trillion over eight years. That falls short of Biden"s current $1.7 trillion proposal on infrastructure investment, which includes massive spending to fight climate change and provide more care for children and the elderly. Progressive Democrats in Congress said they may not support a package that does not address those priorities. Senator Bernie Sanders raised eyebrows on Thursday by saying he is drafting an infrastructure package of up to $6 trillion, beyond even Biden"s initial ask. That measure was sure to be rejected by Republicans and it was unclear how much support it would gather among Democrats. A draft proposal of the bipartisan deal being circulated among members of the group includes $579 billion in new spending, to be paid for in part by unspent COVID-19 relief funds, public-private partnerships and an infrastructure financing authority. The biggest chunk of the money, $110 billion, would be spent on roads, bridges and major projects, according to the draft. Another $66 billion would be spent on passenger and freight rail and $48.5 billion on public transit, according to the draft proposal. The bipartisan plan would be funded by a variety of revenue-raisers. Some of them have been controversial, including indexing the gas tax to inflation. Sources familiar with the negotiations stressed that the document was a draft put together by one member for consideration, and there have been no final decisions. Schumer said Democrats were working on two infrastructure "tracks" - a bipartisan bill and a larger one that could be passed with only Democratic votes using a process called "reconciliation." "We"re trying to get both of them done. We have to get both of them done," Schumer said. Reporting by Susan Cornwell Our Standards: The Thomson Reuters Trust Principles.