There is an Invisible Speed-Signal V2 (kuid2:137715:23002:2) which allows you to set different speeds on sections of track covered by this Speed-Signal based on the priority setting of the consist. The default priority when you add a consist is 2 but you can set the priority of the consist to 1, 2 or 3 with the properties button (?) of the locomotive or traincar in Surveyor and set the three different speeds you want for each train priority in the properties settings of the Invisible Speed-Signal.