Mail Rail to get second act?
 

This might not have been as far fetched as you might think and was clearly worthly of some small consideration. Look at the attached excellent 3D schematic from the crossrail website and you will see just how the line runs in relation to liverpool street. Mail Rail is in pink and Crossrail in the Bluey Grey colour

http://www.crossrail.co.uk/80256B090...reet+3d_lg.jpg