Can anyone tell me of another terminal layout more efficient than this one?
I can think of two that used to exist in NYC. Sands St upper level and Park Row. Both operated in excess of 40 tph. The Park Row terminal operated at 90 tph peak and averaged 40 tph over 24 hours.
Sands St-upper level was a two-track loop terminal with separate inbound and outbound platforms. Park Row was a 4-track relay terminal with a 2-track relay.
Alstom is designed to handle 70 second headways or about 51 TPH, although in practice the minimum headway they have been able to achieve is 92 seconds (40 TPH) on this particular line, mainly because a delay as small as 15 seconds could backup the entire line.
Minimum headways are essentially determined by acceleration rate, braking rate and dwell time. Most operating equipment is remarkably similar for the first two parameters, each being a nominal 30 seconds. Finally, station dwell time is usually set at 30 seconds bringing the total to 90 seconds for 40 tph.
I'm not surprised that they can operate at only 42 tph, regardless of Alstom's design criteria. The only system that I know of that consistently operated way in excess of 40 tph was the BRT over the Brooklyn Bridge. They achieved this by using 4-track stations instead of 2-track stations. This effectively doubled their capacity without the necessity of running 4 tracks over the Brooklyn Bridge.
Recovery time (the time that a leader can be behind schedule without delaying its folower) is simply the difference between the scheduled headway and the minimum headway. If a system is operating at its minimum headway, then there is no recovery time.