Urban D Kaye wrote:A brief addendum to Glenn's post...
In creating m.u. pairings, Septa tends to try and pair like with like--Silverliner II's together, and so on, I believe because their systems are more compatible.
The Silverliner II and III cars often run in mixed consists, and you occasionally see them mixed with the IVs--there's no obstacle to doing so, but the IVs have power doors with MU control while the others are manual.
Before the interior rebuild, you used to have a portion of the Silverliner III fleet, the Harrisburg cars with 2-2 seating, assigned primarily to Airport service--they had yellow "PHL" bands on the ends.
While we're speaking of end bands, only PCB-free cars are allowed in the new yard at Frazer. Those cars used to be marked with blue tape stripes on the ends, but now they have numbers in the 400 series, which makes it easier for the dispatchers to know which cars are permitted there. So for that reason, you'll see mostly Silverliner IVs on the Paoli line.