PORTSMOUTH — Even after lying deep beneath the surface of the Piscataqua River for nearly 80 years, the rusted and decaying axles of a long lost iron horse, still give off a smell of industrial oil.

On the evening of Sept. 10, 1939, Boston and Maine passenger train No. 2024 left North Berwick en route to Boston with only 12 passengers and a crew of five. The train would never arrive.

According to author William Brooke writing in Volume 18 edition 1 of the “B & M Bulletin,” the train was crossing over a 100-year-old wooden trestle known as the “Portsmouth Bridge” and was 40 feet above the river. Brooke said barges used for the ongoing construction of the original Sarah Mildred Long Bridge were anchored to the bridge, which had already been weakened following a collision with a freighter in 1937.

“While crossing the old wooden bridge […] a section of the structure collapsed. Engine 3666 and the first car – a wooden coach with open ends – disappeared beneath the swirling tide, drowning both the engineer and fireman,” Brooke wrote. “The train's two remaining cars were abruptly and miraculously halted at the shattered brink when the brakes were automatically applied by the bursting air hose. Fortunately, no passengers or trainmen occupied the first car.”

The Portsmouth Herald reported in the Sept. 11, 1939, evening edition, “The train was traveling at about 3 miles per hour, officials said, which was the order for trains during the past several years because of the condition of the bridge. Only a few moments after the front section of the passenger train plunged into the water as though thrown from a catapult, the fireman was heard screaming for help as the incoming tide swept him upstream. Automobile lights were directed across the water in the direction of the screams but all witnesses said they could see was the splintered debris if the wooden bridge being swept towards Great Bay.”

The body of fireman Charles D. Towle, an Exeter resident, was recovered the next day around Dover Point and Somerville, Massachusetts, native and engineer John Beattie's body was not found until 10 days later when it was found floating near the Back Channel.

Engine 3666, resting in its watery Piscataqua River grave, has captured the imaginations of history buffs all over the city, and now its story is being brought to a little more closure as a result of the new Sarah Mildred Long Bridge's construction.

During routine dredging in March and mid-October this year for the construction of piers 17 and 18, which make up the center draw span on the bridge, wheels from Engine 3666 were dug up from among the debris.

Ron Taylor, Maine Department of Transportation resident engineer running the SML Bridge project, said in March construction crews dug up what was 3666's pilot wheels and in October trucks from the locomotive's coal tender were recovered.

“We were digging to meet the permitting requirements for the center piers and we discovered the wheels among the debris,” Taylor said. “There was no intentional effort by us to recover part of the train.”

Taylor said all of the train parts were being left on the New Hampshire State Pier and as the project continued along, the pier asked MDOT to consolidate their materials and the wheels were moved to nearby Albacore Park.

According to Taylor, the 18-foot tall Engine 3666 was moved in the 1960s to better clear the navigational channel and in the mid-1990s the train had to be moved again for the New Hampshire Port Authority's pier expansion, but efforts to raise the locomotive to the surface were too costly.

However, now that pieces have been recovered, Taylor said the wheel sets will be donated to the Kittery Historical and Naval Museum and the other set will be stored at the Albacore Park through the winter.

“I would have loved to display them here but there isn't much synergy between submarines and trains,” said Ken Herrick, president of the Portsmouth Submarine Memorial Association, which operates Albacore Park. “But, it's a really interesting part of our history and I hope the city can find a way to showcase these wheels.”

Herrick said he offered the wheels at Albacore Park to the city and Economic Development Program Manager Nancy Carmer said she was in favor of incorporating the train artifacts into the new park being built along Market Street near the new Sarah Mildred Long Bridge, which is in “phase two” of the project and is included in the city's capital plan.

“The pieces are certainly appropriate there, and we're willing to learn more about the event and incorporate it into the future plans,” Carmer said. “It will be in addition to the natural and maritime features of the Great Bay estuary we are looking to showcase down there.”

The Kittery Historical and Naval Museum's director Kim Sanborn said when the museum opens for the spring season visitors will get to see the wheels set up on a small rail spur local railroad buffs constructed for the display outside the museum facing Town Hall.

“Before the Sarah Mildred Long Bridge, this was the main source of transportation across the river when the only alternative was to wait for a ferry in the days before the Memorial Bridge,” Sanborn said. “I'm very excited to be able to tell this story and it really puts the history into perspective when you have the visual component to the story you're trying to tell.”