The city of Bellevue has released drafts of a proposed agreement between Sound Transit and the city to finance a $300 million downtown tunnel.

The council has the option of passing the agreement, asking for more time, or taking no action at all at its meeting Monday night. Councilmembers have voiced their intention to ask for more time on negotiations.

As described by the agreement, Bellevue would be responsible for as much as $160 million of the tunnel’s projected cost. $100 million of that would come in 2014 or 2015 through actions such as donation of land and utility improvements

The rest of the money will be used as a contingency cost. It will be the last source of funds for tunnel construction, according to the agreement, and if costs go down, the city won’t have to put forth the full amount.

The agreement does not express in detail which new design elements the city prefers. According to the agreement, Bellevue wants a trench that goes under Northeast Fourth Street, but it does not specify how and when the track will cross 112th Avenue from east to west.

The document features several “off ramps” wherein both parties can terminate the agreement. The city gets an out if Sound Transit refuses to adopt the city’s requested design changes. Sound Transit can drop the agreement if Bellevue does not grant a number of permitting changes by the end of 2012, according to the agreement.

Sound Transit is expected to act on the agreement at their Oct. 27 meeting.