On March 1, 1862, about two weeks after emigrating from Canada, he was employed as a fireman by the Atlantic and Great Western Railroad, subsequently the Erie Railroad and now (Jan. 10, 1964) known as the Erie Lackawanna Railroad. Throughout his life the Erie was his only employer. He was promoted to Engineer but the records of the Erie do not show the date of his promotion.

On Saturday morning, March 30, 1901, while at the throttle of the New York and Pittsburgh Express out of Cleveland, his train struck a freight train at Phalanx Station, near Warren, Ohio. He had been able to greatly reduce its speed before the collision. but jumped nevertheless at the moment of impact and was thrown heavily to the ground breaking his right leg at the ankle. He was taken to St Vincents Charity Hospital in Cleveland, and was brought home the following May. However the injury had not healed and amputation of his foot was discussed. His wife, Mary Larkin, rebelled, and on June 3 had him taken to City Hospital in Youngstown. His recovery was very slow, and he was finally brought home on January 14, 1903, after almost two years.

For the rest of his life he walked with a limp, as his right ankle was stiff. It should be added that after the accident a wrecking train from Cleveland was sent for, which was brought down by Alexander's brother, Hugh Larkin, who was also an Erie engineer. Alexander Larkin resumed work, and his career was climaxed when his name was placed on the cab of his engine. He retired April 19, 1913, at the age of 70, having served the Erie Railroad for 51 Years. His last years were spent at 7805 Melrose Avenue in Cleveland.

Following is a newspaper clipping, hand-dated 1911, probably from the Cleveland Leader, where his son worked:

The Erie Railroad made Alexander Larkin, one of its engineers, a birthday present of a 118-ton engine. The gift is in remembrance of his 68th birthday and a token of appreciation of fifty years of faithful service. The engine will be his to run and no one but himself will ever use it while it is his.

Engineer Larkin is what railroaders know as a "born-runner". He has a peculiar ability that few are born with and none acquire, to make fast time. In his fifty years of pulling trains, the most have been fast trains, and he established a record of never having had a passenger killed behind him. He established the present record between Cleveland and Pittsburgh, sixty one miles in seventy one minutes. His speed indicator often registered 68 and 70 miles an hour.