Northern Light
Superstar
Indeed. Actually installing the doors is cheap.
Last time I saw a breakdown (IIRC Miller was mayor) a lot of the cost was asbestos removal, structurally reinforcing the platform edges, running electrical and network conduit, and fire/smoke handling improvements for the tunnel.
I concur w/this; though would note, a whole of ventilation improvement has been invested in for the last 10 years;
Also, the project scope should be the same now as 10 years ago, but the estimates per station are over triple (inclusive of future year inflation); on constant scope, that rate of increase seems dubious.