A major wrinkle has developed in the debate over the location of an intermodal transportation hub in Salt Lake's Gateway area, just one week before a final decision is scheduled on the issue.

A consultant brought in by four groups championing the Union Pacific Depot for the hub location Monday proposed a commuter rail hub on 500 West between North Temple and South Temple - a location that has not been considered before.The idea has caught the fancy of City Councilman Roger Thompson, who is the swing vote on the hub location.

"I must say I'm leaning their way," he said.

The hub's location has been the subject of considerable debate during the past few months. It has boiled down to two possible locations: 600 West and 200 South, next to the freight line tracks, and the Union Pacific Depot. Excluding Thompson, the council has been split right down the middle on the issue.

Proponents of the Union Pacific depot say the 600 West/200 South location would kill commuter rail on arrival because it is too far from downtown. Those on the other side - which include Salt Lake's planning staff and consultants - counter that the depot, while attractive and closer to downtown, is logistically not doable.

What Roger Millar, a transportation consultant from Portland, Ore., proposed Monday was a compromise. Keep the Amtrak hub at 600 West and 200 South, he said, but move the commuter rail hub to 500 West, which is less than a block from the depot. He said the location would have various advantages:

- It would not require tracks through the Boyer Co.'s large proposed development of the rail yard west of the depot. Boyer vigorously opposes the depot location for that reason, but the 500 West location "is fine by us," said Stephen Caine, Boyer's special projects director. "It doesn't interfere with our development at all."

- It could be kept at grade, eliminating the need for a proposed $130 million tunnel.

- It would use the land between South Temple and 100 South and 500 West and I-15, which is undesirable for developers because it will be bounded by a highway, an on-off ramp and train tracks.

- It would be close enough to the Union Pacific Depot that commuters could walk to it, and from there get on either the north-south light-rail line or the proposed east-west line.

Nevertheless, the location does have problems.

Deputy Salt Lake Mayor Brian Hatch noted it would reintroduce tracks to the area, after years of effort to clear them, and there would be a lot of right-of-way acquisition needed for the tracks and hub. "With the other site we have a willing seller," he said.

In addition, the federal government has so far balked at providing funding for more than one transportation hub. Given the projected low numbers of initial commuter-rail users (about 4,000 daily), "to date (the feds) have not seen the need for two rail stations within a quarter-mile of each other."

Finally, the tracks would interfere with the touch-down point of a proposed I-15 high-occupancy vehicle on-off ramp at 100 South and 600 West. Utah Department of Transportation officials have said they don't want tracks interfering with the ramp, though Millar said the two could be designed to be compatible.

The solution to the knotty problem, according to City Council Chairman Bryce Jolley: Follow the city Planning Commission's recommendation of locating the hub at 600 West and 200 South, but keep the 500 West option open for the future when increased ridership might merit the increased cost.

"This alignment here is something that can happen almost at any time," he said.

Hatch agreed.

"The Planning Commission outlined the appropriate vision for the future," he said. "When ridership builds and we can justify a second station, we can come back to it."