of the 57 locomotives, 44 of them had been upgraded to the version, while the remaining 13 still have the original power. Names After introduction the locomotives were named after opera singers. In 1997 four units were named Jungfraujoch, Lötschberg, Gotthard and Furkatunnel, after Swiss rail tunnels. List of Named locomotives: Notes References Sources Literature Further reading External links 9 Bo′Bo′Bo′ locomotives Bo-Bo-Bo locomotives Brush Traction locomotives Channel Tunnel Railway locomotives introduced in 1992 Standard gauge locomotives of Great Britain Standard gauge electric locomotives of France