Editor’s Note: “Off Track,” our investigative series examining what’s happening to $6 billion in taxpayer money that is going into the biggest public works project in Hawaii history, continues today with a look at campaign contributions from contractors to local politicians. That may seem like an obvious political story but our larger question remains: Is the Honolulu rail project boosting the economy — as Oahu voters were promised — or just fattening the campaign treasuries of politicians in a position to hand out lucrative contracts? We need your help to figure out who’s really benefitting from the rail project. Check out the list of companies posted at the end of this story. Who are these companies and are they really locally owned and operated? Have you or anyone you know gotten a job with any of them? Do you own or work for a business that has benefitted from rail money? Increased sales? Better salaries? What are some of the economic indicators you’ve seen that would suggest rail is having an impact on our economy? Help us tell this important story through crowdsourcing. Post your thoughts in the comments section below or send a note to Nick Grube at nick@civilbeat.com. Continue the conversation through Twitter or Instagram using the hashtag #railtalk.

Many of the companies snatching up contracts as part of Honolulu’s $6 billion rail project are also the same ones plumping up the campaign coffers of local politicians.

A handful of Hawaii-based businesses alone have padded the war chests of top officials, such as Mayor Kirk Caldwell, Gov. David Ige and his predecessor Neil Abercrombie, with more than $1.3 million in contributions since 2006, according to data analyzed by Civil Beat.

Once the contracts are fully executed, those companies are on track to receive tens of millions of dollars in taxpayer money to work on the rail line.

While it’s not uncommon for companies with interest in government contracts to give generously to candidates whose political leanings can bolster bottom lines, questions have been raised about just how close these ties are, especially when it comes to rail.

Honolulu rail contractors spend heavily on local politics.

Cory Lum/Civil Beat

In 2008, the city released records showing who had received millions of dollars worth of subcontracts to do preliminary planning work and public outreach on the rail project. One in three of those contracts went to companies or individuals who had donated campaign funds to then-Mayor Mufi Hannemann, according to a Honolulu Star-Bulletin review of the records.

Hannemann defended the contributions at that time, saying the donations were legal. But that didn’t stop Honolulu City Council members from sounding the alarm about the close ties between the mayor and some of the subcontractors.

While its relatively simple to track campaign contributions made by rail contractors, it’s nearly impossible to see how much all of these companies are making.

The Honolulu Authority for Rapid Transportation has said it doesn’t track payments made to subcontractors. HART recently released to the City Council a list of local companies that have worked on the rail project, providing contract amounts for some of the businesses.

Of the 27 companies with $1 million or more in rail contracts, principals or employees from 17 of those businesses have donated to local politicians since 2006.

About $375,000 worth of contributions came from people associated with R.M. Towill Corp., a Honolulu-based engineering consulting firm that has at least $4.9 million in rail contracts.

That’s nearly twice as much money in campaign contributions than was given by people associated with Bowers + Kubota Consulting, which comes in second on the list of top donors. Bowers + Kubota has at least two subcontracts, one of which amounts to more than $6.6 million.

The biggest beneficiaries of R.M. Towill campaign cash have been Caldwell and Hannemann, each of whom received more than $70,000 in donations. But company affiliates have also donated heavily to Abercrombie, Ige and Honolulu City Council Chairman Ernie Martin.

R.M. Towill’s top political donors are president Greg Hiyakumoto and vice president Collins Lam, a former Hannemann cabinet member who served as deputy director of the city’s Department of Design and Construction.

Here’s the full list of local prime contractors and subcontractors HART provided to the Honolulu City Council. Not all contract amounts were made public.