Original sentence: As HS1 and HS2 will not be integrated, HS2 Ltd proposed to enhance links between HS1's terminus at St Pancras and HS2's terminus at Euston which are separated by the British Library on Euston Road; at their closest points, the two high-speed lines will be only  apart.The two termini will also be served by the same station—Euston St Pancras—on Crossrail 2, which could provide a covered connection
Edited sentence: In the absence of a heavy rail link between the two lines, HS2 Ltd proposes to enhance the links between HS1's terminus at St Pancras and HS2's terminus at Euston which are separated by the British Library on Euston Road; at their closest points, the two high speed lines will be only  apart.The two termini will be served by Euston St Pancras should Crossrail 2 be built