I have heard it said that there is no signalling on this line north of Aurora. If this is true, does signalling need to be installed to have bidirectional traffic?
The information that I have shows that north of CN CONCORD (Mile 15.5) the tracks is under Occupancy Control System rules. This means that trains have to call in and receive verbal clearance to proceed. In theory it doesn't need to be upgraded if all trains are always on time, but reality is very different.