Catoe indicated in his final Lunchtalk chat that the Dulles extension would have cement cross-ties.
That's great to hear! Does anyone know how much that might increase the speed limit from what it would be with wooden sleepers?
Based on the data I have seen in the curve table in Volume IV, Chapter 3, Plan and Profile
(54.4 MB PDF file) of Final Environmental Impact Statement there will be no difference in maximum speeds.
Maximum speeds will be 75 MPH like it is on many other parts of the railroad before those speeds were reduced to save energy costs (electricity) and to reduce wear and tear on the trains and track.
50 MPH inbound track N1 under Haycock Road
50 MPH I-66 flyover
60 MPH VA-267 near Idylwood Road
50 MPH VA-267 south of Chain Bridge Road
45 MPH VA-267 VA-123 interchange flyover
45 MPH Tunnel between Tysons 123 (Tyson Center) and Tysons 7 (Pike Seven Plaza)
40 MPH VA-267 VA-7 interchange flyover
70 MPH VA-267 west of VA-7 interchange
70 MPH VA-267 west of Trap Road
70 MPH VA-267 east of VA-28
45 MPH just in side tunnel portal east of Dulles Airport
40 MPH in tunnels east of Dulles Airport station
40 MPH in tunnels west of Dulles Airport station
70 MPH north of Dulles pocket track
50 MPH south of VA-606
All other curves along the alignment with exception of the most of curves within 400' of platforms are 75 MPH.
John in the sand box of Maryland's eastern shore.