by Terry Kennedy
nyrmetros wrote:When PATH was first built, was there a choice between CTA and 3rd rail ?PATH inherited the whole system from the H&M, except for the WTC station which they built to replace Hudson Terminal.
The original (1874-1882) phase of construction (pre-H&M) intended to use full-size steam equipment. The next attempt re-used the original work, but stepped down to a smaller size tunnel. By the time the H&M came along and started construction, they stepped down again. One of Jacobs' ideas was to run two "midget" cars side-by-side in a full-sized tunnel (the one that was furthest along - what is currently the NJ-bound side of the 33rd St. service). He gave up on that idea well before the H&M started any construction, instead going with (mostly) IRT-sized equipment and tunnels.
There's no clearance in tunnels like that for catenary. Not to mention the problems that would happen on the curves where a pantograph arm would hit the sides of the iron-ring-lined tunnel. A trolley pole with a single overhead wire (like the pre-reconstruction Newark City Subway) would have been technically possible, but not practical with multiple cars. I'm traveling now so I can't check to see if Jacobs' side-by-side sketches included trolley poles or not. I can check when I get home at the end of the month.
Even the 3rd rail has clearance issues - for some reason, the 33rd St.-bound trackage was built very low in the invert around the Morton St. curve - enough that the pickup shoes would hit the sides of the tunnel and arc. Since this is overrunning 3rd rail, the shoes are spring-loaded and will flop down if there isn't any 3rd rail. The H&M's solution was to put in a false 3rd rail made of wood on the other side, to keep the shoes up.
An early 1960's study the PA commissioned for suggestions to improve the system included raising the trackbed in this area, but that would have required service be shut down for an extended period for the re-grading, so the PA didn't do it. This caused a bit of trouble when the PA-1's arrived - the side bulge was intended to be above the level of the sidewall bench, but because the track was so low, lots of the bench had to be chipped away to obtain satisfactory clearance. The PA-series caused some other issues, too - the unidirectional crossover west of 9th St. didn't have enough clearance for them, and since that was actual tunnel rings, nothing could be done and the crossover was eventually pulled up. Even today, if a PA-series train runs westbound through the (normally) eastbound Grove St. station and crosses back to normal west of Grove St., the sway is sufficient to scrape the sidewall at the crossover if run at the maximum speed permitted by the signals.