Action for Public Transport (N.S.W.) Inc.
But the NWRL route was changed even though tunnelling north-west from Beecroft would have required less tunnel than from Epping and therefore should perhaps have cost less. The present tunnels just north of Epping were built with short stubs running towards Carlingford; these are now to be used to start the NWRL. The NWRL in turn is also able to accommodate a possible future connection towards Carlingford and thence Parramatta (see proponent's report on EIS2 submissions, chapter 7).
However, the NSW government's decision to reserve the low-level platforms at Epping for the NWRL, and Gladys Berejiklian's obsession with building the NWRL using single-deck trains in steep narrow-bore tunnels, have restricted the possibilities for Parramatta-Epping.
Because the trains from Parramatta via Carlingford will enter Epping below ground and use the low-level platforms, they will have to be single deck and therefore can't come from west of Parramatta although they might come from the south eventually if Cabramatta-Merrylands is ever converted to single-deck. And they presumably can't go east of Epping because the Epping-Chatswood tunnels are only rated for 20 trains per hour due to safety considerations. Again, Chatswood could not turn more than 20 trains per hour around, given that Sydney's Rail Future (page 12) promises cross-platform interchange there. So the trains will be Parramatta-Epping shuttles into the foreseeable future.
Note that if double-deck trains were used on the NWRL, fewer of them would be needed to carry the same number of passengers and likewise trains from Parramatta to Epping could carry more passengers each and then it might be possible to run trains from Parramatta to Chatswood.
All this means that people from west of Parramatta who want a short-cut to Macquarie or Chatswood will have to change trains twice, amounting to a noticeable penalty in time and convenience. Going beyond Chatswood would require yet another change, certainly until the next stage of Sydney's Rail Future is built, if it ever is. And it might not be built, as future governments are unlikely to see single-deck services to the outer suburbs in the same rosy light as the O'Farrell government sees them.
The other function that a Parramatta-Epping link would have is as a feeder to the Parramatta business district. While that would be all very well, the M54 bus service is a satisfactory substitute and much cheaper.
Meanwhile, Parramatta City Council apparently wants to convert the Carlingford railway into a light rail line from Parramatta to Epping, but that is another story.