LEWISTON — A massive 750,000-pound autotransformer, destined to be installed in locally later this month, is due to arrive in Portland by boat this week.

John Carroll, public information officer for Central Maine Power, said the transformer will be moved to a rail car later this week and moved by train to Leeds.

From Leeds, crews using a specially designed multiple axle truck will begin moving the piece to its ultimate home in CMP’s new Larrabee Road substation May 17 or 18.

“Everything about this is unique,” Carroll said. “The train car itself, I think there are only a couple of them in existence that can move something this big.”

It’s all part of CMP’s $1.4 billion Maine Power Reliability Program. It calls for upgrading a swath of power lines, beginning in Eliot and passing through central Maine to Orrington, where they connect to lines from Canada. Along they way, they pass through Litchfield, Monmouth, Leeds, Greene, Lewiston and a corner of Auburn at the Durham line.

It means four years worth of construction, erecting 442 miles of transmission lines across 75 Maine cities and towns. The entire program should be finished by 2015, with work in Lewiston wrapping in 2014.

When it’s installed, the autotransformer will reduce the voltage along CMP’s network, reducing electricity from 345,000 volts to 115,000 volts, suitable for delivery to the central Maine region.

In Lewiston, the $58 million Larrabee Road project has all been geared toward preparing for the autotransformer’s arrival. That includes digging up the area to bury miles of cables. Much of that work is finished now, Carroll said.

“It’s starting to look like a proper substation site now,” he said.

Crews have finished building the massive concrete pad where the autotransformer will be placed and are currently working to build the breakers that will be connected to the transformer.

“I keep looking at that concrete pad and expecting to see bolts or something,” Carroll said. “I keep expecting something to tie it down to the site, but they don’t bolt this down. It’s too heavy. They don’t need to.”

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