The Electro Motive Division; BL20-2 is a four-axle 2,000hp diesel locomotive built during the 1990's.
Only three were built, and weren't needed on the BN and other railroads to whom EMD demonstrated the units.
They were also originally meant to be standard, prime-mover diesel locomotives, but railroads decided to continue to use their GP (General Purpose) four-axle diesel locomotives originally built by EMD. The locomotives themselves, are rebuilt from older EMD locomotives. The only three built, are still in service, and have been owned by several shortlines and have been renumbered several times as well.
G&W's SJVR currently operates all three as 2120-2122. All three have been repainted into G&W colors.
The name derives from the BL1 and B L2 which were EMD's pre-GP multi-use locomotives.