After the opening debate of Pittsburgh's mayoral election, PG colleague Ann Belser wrote that Mayor Luke Ravenstahl and Republican challenger Mark DeSantis agreed on major transportation issues, to wit:

"That Oakland and Downtown should be better linked by mass transit; that the subway extension to the North Shore is a waste of money; and that the northerly portion of the Mon-Fayette Expressway is dead."

What?

First, regarding Oakland-Downtown, that's what the Port Authority tried to do until politicians stopped it. In the 1990s, the transit agency had already climbed the first several steps toward securing federal approvals and funding commitments for a light-rail line connecting the two urban centers.

But the county's last board of three commissioners, who served before the new county executive form of government took effect, derailed the authority's efforts. As a result, years of work, money and promise were wasted in what would have been the next logical expansion of the transit system.

No city mayor or county official since then has asked or directed the authority to resurrect what was once called the "Spine Line" to Oakland, now at least a $1 billion-$2 billion undertaking that would take 15 years to plan, design and build, even if it were to get back on the federal list of projects competing for limited funds.

Complicated, expensive, major public transportation projects cannot be turned off and on at the whim of every newly elected politician.

Second, although the Port Authority is taking all the heat, the $430 million light-rail extension is being built because the city wanted it, including former Mayor Tom Murphy, after former Commissioners Mike Dawida, Bob Cranmer and Larry Dunn ordered it dropped at the same time as the light-rail line to Oakland.

Pittsburgh elected, civic and business leaders lobbied to salvage the 1.2-mile North Shore Connector as a catalyst for development, although engineers -- not the leaders -- recommended building the controversial twin tunnels under the Allegheny River instead of using a bridge.

The strategy is working, so it's puzzling why Mr. Ravenstahl and Mr. DeSantis would characterize the long-sought project as a waste when the city will be the big beneficiary of linking Downtown to new North Shore developments for decades to come, without costing the city a cent.

Finally, if the 24-mile northern section of the Mon-Fayette Expressway connecting the other 60 miles of the toll road to Pittsburgh is "dead" as Mr. Ravenstahl and Mr. DeSantis said, somebody should tell the Pennsylvania Turnpike Commission.

The northern connection may not be built for another decade, or ever, because its cost has escalated to $3.6 billion. That's partly because of demands, bureaucratic roadblocks and delays attributed to ex-Mayor Tom Murphy, who opposed the toll road.

Meanwhile, the turnpike is still spending more than $1 million a month for 13 consulting firms to continue the final design that will prepare the project for right-of-way acquisition, utility relocation and construction, just in case somebody finds the money.

City officials and city residents are involved in two Design Advisory Teams, formed to make certain that the ribbons of concrete will be as compatible as possible as they slice through the urban environment.

A dozen speakers, including County Chief Executive Dan Onorato, testified in support of the Mon-Fayette Expressway at a State Transportation Commission hearing last month that helps determine the priority and funding for all road, bridge and transit projects.

Neither Mr. Ravenstahl nor Mr. DeSantis was there.

The two mayoral candidates, along with candidates Tony Oliva, of the Libertarian Party, and Ryan Scott, of the Socialist Workers Party, are to appear at a public forum The Post-Gazette will hold at 7 p.m. Tuesday at the Senator John Heinz Pittsburgh Regional History Center in the Strip District.

The two favorites, Mr. Ravenstahl and Mr. DeSantis, need to get their history and facts straight when it comes to transportation facilities that serve as lifelines to any city.

Perhaps this tutorial will help.