The price tag for Salt Lake City's portion of Utah's newest — and smallest — light-rail extension hit some City Council members like a ton of bricks this week.

Council members realized Tuesday that Mayor Rocky Anderson's administration wants taxpayers to spend $8.5 million for a TRAX extension between the Delta Center and the Intermodal Hub, near 300 South and 600 West, now under construction.

All told, federal, state and city taxpayers will pay nearly $35 million for the line, which covers five blocks. That's $7 million a block, slightly less than the per-block costs of the 400 South TRAX line and the University of Utah Medical Center line.

City Council members are wondering if it's worth it and whether the city should be paying more for the line than the Utah Transit Authority is paying — $5.2 million — the money left over from the medical center line for the extension.

"That's the first time somebody's hit me with an $8.5 million price tag for something which quite frankly I'm not sure how many of our residents are going to use," Councilman Carlton Christensen said.

Christensen said many city businesses would benefit from the line but, "It's such a huge price tag I want to make sure we're not unfairly picking up costs that may be someone else's."

Federal money is expected to cover roughly $20 million of the project.

In the past, the Utah Transit Authority had paid for most, if not all, the road reconstruction costs associated with TRAX installation. Now, however, because UTA has so many light-rail projects in the works, they are unwilling to pay for road reconstruction or utility removal, leaving those costs for the city, UTA spokesman Justin Jones and DJ Baxter, Anderson's senior adviser, said.

"We need to spend less, and I think we can spend less," Councilman Dave Buhler said.

But Baxter said the price is pretty much set.

"Again what we are talking about is the cost of street improvements, so they cost what they cost," he said.

Baxter and several City Council members wondered if UTA could pay more, noting that UTA needs the line a lot more than Salt Lake City does.

"I would have to say this little leg is probably more important for their whole transportation system to connect those lines together than they allude to in public," Christensen said.

But Jones said it's the city that wants the line so bad, not UTA.

"It's not part of the Wasatch Front Regional Council's priority list," he said.