Police Dog Jet, a six-year-old German shepherd, was killed following a burglary at a commercial property in Yate, south Gloucestershire.
While pursuing the suspects, PD Jet ran on to an obscured section of track and was hit by the locomotive.
Avon and Somerset Police said the animal was struck on Wednesday morning. After getting emergency treatment the decision was made to put PD Jet to sleep.
He had joined the police force a year ago.
The suspected burglars are still at large and officers are trying to find them.
Chief Inspector Jason Shears said: “We are incredibly sad at the loss of PD Jet.
“Jet was a determined and focused police dog who loved working in the many important roles our dogs perform in, all of which help to keep our communities safe.
“Jet and his handler had a very special bond which was cemented by the months of hard work and training carried out.
“Jet will be missed by all within Avon and Somerset Police.”
Source: (Sky News)