Polar Bear is a battery-electric locomotive built by Alan Keef

Alan Keef

Alan Keef Ltd is a British narrow gauge railway engineer which manufactures, overhauls and deals in narrow gauge locomotives, rolling stock and associated equipment....

 in 2003 for the Groudle Glen Railway

Groudle Glen Railway

The Groudle Glen Railway is a narrow gauge railway north of Douglas in the Isle of Man which is owned and operated by members of the Isle of Man Steam Railway Supporters' Association and operates on summer Sundays; May to September and Wednesday evenings in July and August along with a number of...

 in the Isle of Man

Isle of Man

The Isle of Man , otherwise known simply as Mann , is a self-governing British Crown Dependency, located in the Irish Sea between the islands of Great Britain and Ireland, within the British Isles. The head of state is Queen Elizabeth II, who holds the title of Lord of Mann. The Lord of Mann is...

, where it currently resides. It was built on the frame of a 1988-built vehicle of similar design (one of the last to be built) and has a newly-fabricated body replicating that of two similar locomotives that operated the railway between 1921 and 1926. The original was built by Wingrove & Rogers

Wingrove & Rogers

Wingrove & Rogers Ltd of Kirkby, Liverpool, built industrial vehicles including both small electrically motorised trolleys and electric locomotives , largely for use in mines and by tunnelling contractors....

in 1920, and allocated works no. 314 and the operating replica is in original form. However, the 1920 version proved troublesome and within the first season had been modified to include bogies to reduce the uncomfortable ride. Further modification came with the addition of a battery truck that the loco pushed around, though the replica does not carry these later features.