Complex sentence: At that time, the oldest 12 HSR trains will be retired and 14 new HSR trains will be deployed increasing the total capacity to 46 HSR trains which will cutthe travel time from Boston to Washington, DC to 3 hours and 8 minutes.
Split into simpler sentences: At that time, the oldest 12 trains will be retired and 14 new ones will be deployed increasing the total capacity to 46. This is projected cut the travel time from Boston to Washington, DC to 3 hours and 8 minutes.