A map shows an additional north south runway, at about 80 degrees to the existing East West runway.
This new runway would require the railway and road to be put into tunnels.
Ideally, the new airport terminal would be on the south east corner of the two runways, adjacent to Clarendon station.
To improve the railway service, the remaining single line sections out to be duplicated, except perhaps for the long viaducts on either side of Windsor station. The line is now double track as far as Schofields. There are crossing loops at:
* Riverstone - 2 side platforms
* Mulgrave - 1 island platform
* Clarendon - 2 side platforms
* Richmond has 2 deadend (island) platform.
The Richmond airport would be a temporary affair pending construction of Badgerys/Wilton, which require considerably more infrastructure.