Honolulu has wasted so many years ruminating over rail transit that there's no need to dither further before coming to the point: It's time to take off the wheel blocks and get rolling with this thing.

The latest distraction is over the decision to construct an entirely elevated system, rather than running portions of the line at-grade. Comments from a group of Honolulu architects and from landowner Kamehameha Schools have urged a second look at bringing the train down to street level along portions of the route.

That option is neither cost-effective nor the right choice for Honolulu. Point by point, here's why this is more of a distraction than a productive discussion:

Cost: Advocates of a system that runs partly at-grade estimate that it could save a significant share of the projected $5.3 billion cost. But as planners and engineers correctly observed, the at-grade segments would require far more land acquisition and extensive excavation to lay the foundation for the rails — unearthing utilities and disturbing burial sites that are known to be numerous in the midtown district. The additional land acquisition costs, relocating utilities and sewers, as well as costs and delays associated with buried iwi are sure to be expensive and pose far more disruptions than installing the concrete support piers at intervals for the elevated system.

Taxpayers cannot afford the additional land condemnation, in the pricey Downtown area, that at-grade segments would require.

Capacity: Bringing the train down to street level would defeat the purpose of building it in the first place: transporting large numbers of O'ahu commuters quickly and reliably between the west side and urban Honolulu. The at-grade train cars with the capacity to do that are longer and wider than can be readily accommodated on existing streets.

Speed and reliability: At-grade systems also must operate at much slower speeds and mesh with cross traffic at busy intersections, a fatal blow to reliability and ultimately ridership. Allowances for private vehicles to enter and exit driveways would have to be made, and the train would be prey to the same in-town traffic jams that its riders are hoping to avoid.

Why bother? With this approach, the city would be unable to deliver trains every three minutes as hoped, drastically reducing the numbers who could ride and making the commute far less reliable.

Federal approval: Ultimately, a change in technology would mean the city is redefining its entire mission, which would force the entire process of federal review to begin again from square one. The project would be greatly delayed — if not entirely defeated.

That's something we simply can't afford to let happen. Staying on track and starting construction this year would immediately create much-needed jobs and a financial infusion our economy can ill-afford to lose.

This isn't Phoenix or San Diego or San Jose whose at-grade systems function more as people movers. Our needs are entirely different, not to mention our higher land costs and our linear urban core.

So here are the facts.

Honolulu has spent decades talking about and studying a rail system. This one is well planned and has received accolades from transit planners and engineers here and in other cities, and federal transportation officials say the project makes sense and is worthy of support. The city has worked diligently on behalf of taxpayers to meet all the stringent federal requirements thus far.

What's more, a roundtable of some of Hawai'i's top business professionals did an independent analysis of the city's financing plan and found it to be solid and prudent. The group made its own adjustments — taking into account lower tax revenues brought on by the economic slump, as well as lower construction costs that would benefit the project — and has given the project high marks. In addition, the financing plan includes a wide allowance for cost overruns. These experts also say we could receive a greater-than-budgeted share to come from the federal government. By all accounts, it's well positioned to receive funds as a transit "new start."

So let's start, already.

The city has done its homework, and the will to proceed is there at last. Let's not waste time and precious dollars with this political paralysis.

The decision is made, and it's high time for the follow-through. Let's move on and make rail happen for Honolulu.