Quote:
Originally Posted by Nouvellecosse
Good point on the car length. I saw they both have six car consists and the cars looked similarly long so i didn't consider there would be a significant difference. I'm also surprised the peak frequency is only 4 minutes. In many cases frequency is limited by the availability of rolling stock, but in this case 4 minutes is the minimum for the signalling system?
|
I don't know if it's a limitation of the signal system. 'Popular' holding among local transit advocates is that the M4 cars are lemons. (There was
a story about two and a half years ago about cracks in their bolsters) Each costs more to maintain than the BIVs, which are about fifteen years older, and they have about half the mean distance between failures (I.e. ~120,000 for the BIV cars, but ~ 60,000 for the M4 cars). I once read an old fleet management plan submitted to the FTA for the M4 cars that indicated that mean distance between failures, which was ~60,000 at time of purchase, was expected to better with experience and that they were intended to support three-minute headways. The MFSE ran much more service in the past. I recall reading a report from before 1920 about the PRT running 40 cars per hour, which William S. Twining, Phialdelphia's second Transit Commissioner, thought improvements could be raised to 44 trains per hour, which was desired as contemporary plans called for the planned, but never built, Darby Elevated, mostly to run along Woodland Avenue, to begin as a branch of the Market Street Subway-Elevated until demand made a dedicated route to Center City, which was variously planned as a Chestnut Street Subway or branch of the South Broad Street Line. (A local transit activist has made
a very handy series of representations of various historical plans using Google Maps)
SEPTA has 218 M4 cars in service, two having been reassigned to be work cars. It's worth noting that the Broad Street Subway runs about eight five-car local trains, eight five-car express trains and nine two-car Ridge Spur trains (Crudely, ~ 98 cars per hour) with a fleet of 125 BIV cars, but the Market-Frankford Subway Elevated runs fifteen hourly trains (Crudely, ~90 cars per hour) with a fleet of 218 cars. Something about the terminal configurations at 69th Street and Bridge Street (*achem* "Frankford Transportation Center), might account for some of the difference, but that seems inadequate to explain everything. I imagine that multiplying trains per hour by cars per train is inadequate to fully understand the number of cars needed for service, but comparing the ratio of that to fleet size is suggestive. By that crude methodology, the BSS operates with a ratio of 78.4 % of its whole fleet, but the MFSE only 41.3 % of its fleet. Unless the M4 cars are too unreliable or they have too few drivers, it seems that SEPTA should be able to run better frequency on the MFSE. (Worth noting is that General Manager Knueppel's overwrought scheme to lengthen the trains to eight cars also calls for acquiring more MFSE cars and adding yard space; both seem awkward the justify as 218 cars seems like it should be enough for longer trains, even if terminals limit frequency, and the M3 fleet comprised 270 cars)
Prev
Linear Mode
