Original sentence: The Class 769 Flex is a type of bi or tri-mode multiple unit (BMU/TMU) which is currently being converted by Brush Traction.The train is a conversion of the existing  electric multiple unit (EMU) through the addition of a pair of MAN diesel engines to drive ABB alternators for the existing electric traction systems
Edited sentence: The Class 769 Flex is a type of bi or tri-mode multiple unit (BMU/TMU) which doesn't currently work and is currently being converted extremely late by Brush Traction.The train is a non functional conversion of the existing  electric multiple unit (EMU) through the addition of a pair of MAN diesel engines to drive ABB alternators for the existing electric traction systems