When the news broke about the escalating costs of the MBTA's Green Line extension to Medford and Somerville, I can't say I was surprised, but the cost numbers have now escalated in to absurdity. I'm not an expert in the bizarre project procurement, but the costs are now to the point where the project really should be reviewed and rebid, even if there is a delay. It is far beyond what similar projects cost in other cities, and the project procurement team at the T should be removed to allow someone from the outside to bid the project.How ridiculous are the T's numbers? Let's take a look at them, and compare them with some other projects:Green LineDistance: 11 milesCost: $957 millionCost per mile: $87 millionCompletion date: 2014Engineering difficulties: rebuilding bridge over Mississippi River for light rail, rebuilding the entirety of University Ave lot line-to-lot line, junction and flyover with existing Blue Line in Minneapolis. Likely cheaper than the Green Line extension. But not 9 times cheaper.Distance: 6.6 milesCost: $1.5 billionCost per mile: $227 millionCompletion date: 2016Engineering difficulties: Several grade separations, parallel bike/walk facility. Still four times cheaper than the GLX.Distance: 1.7 milesCost: $1.6 billionCost per mile: $941 millionCompletion date: 2019Engineering difficulties: full deep bore tunnel in a seismically active area with three underground stations. In a rather expensive city to work in. And barely more than the GLX, which is being constructed in a grade-separated right of way!Distance: 3.1 milesCost: $1.9 billionCost per mile: $613 millionCompletion date: 2016Engineering difficulties: full deep bore tunnel below the water table in a seismically active area with two underground stations. And quite a bit cheaper per mile than GLX.Now, here are two MBTA projects:Distance: 1300 feetCost: $750 millionCost per mile: $3 billionCompletion date: ???Engineering difficulties: Cut and cover tunneling below the water table in a constrained corridor. Certainly no greater than building the Central Subway in San Francisco, yet somehow three times more expensive. This should probably be in the lower end of the $100 to $200 million range, not three quarters of a billion.Distance: 4.3 milesCost: $3 billionCost per mile $700 millionCompletion date: 2019?Engineering difficulties: Relocating existing parallel commuter rail line, building a flying junction, parallel bike/walk facility.Here's the thing: none of the engineering challenges faced by the GLX and RBC are unique (flying junction in Minneapolis, parallel path in LA) or insurmountable, yet the costs are an order of magnitude greater than in other cities. The Green Line Extension is between three and nine (!) times more expensive than similar light rail lines, and more expensive than new light rail lines which are being built using deep bore tunneling techniques, which arecheap. High construction costs? Seattle and San Francisco have pretty high construction costs and labor wages too. The remaining GLX construction should be rebid mimicking the processes used in these cities with a new team at MassDOT, and if costs aren't cleaved significantly, there should be a full investigation as to why.The for the Red-Blue connector, which everyone agrees is a very important link, somehow costs three to four times what much more complex projects cost in Seattle and Los Angeles (while the Blue Line uses heavy rail equipment, it is the same diameter as light rail trains). The project is only 1500 feet long, doesn't require a deep bored tunnel, and has only one station at Charles, and the headhouse there already exists with provisions to connect it to the Blue Line. The fact that it costs $2.6 billion dollarsis laughable. For the cost of one mile of construction in Boston, Minneapolis could build 30 (!) miles of light rail, and Seattle four miles of deep bore tunnel (about what you'd need for the North South Rail Link ) and at a cheaper rate per mile than the Green Line Extension. It's not even in the ballpark of reality, and whoever at MassDOT comes up with these numbers needs to be sent out to pasture.There is no logical reason why a project in Boston should cost triple—or more—what a similar project costs in another city. $2 billion was suspiciously high. $3 billion means that a lot of people are on the take, or that money is being pissed away. I'm all for transit expansion, but not at these prices. An outside manager is a good start. But this has been a problem for a long time, and the T's project procurement staff has shown no ability to do their jobs. Get rid of them.This is correctable. It needs to be corrected.