[From nobody Mon Jan 14 08:17:49 2013 Received: from mta3.snfc21.pbi.net (mta3.snfc21.pbi.net [206.13.28.141]) by mail-sf1.pacbell.net (8.9.3/8.9.3) with ESMTP id JAA08502 for <pghpcc@mail-sf1.pacbell.net>; Wed, 24 Nov 1999 09:28:31 -0800 (PST) From: JacksoRE@STVINC.COM Return-receipt-to: JacksoRE@STVINC.COM Received: from wodc7-1.relay.mail.uu.net ([199.171.54.114]) by mta3.snfc21.pbi.net (Sun Internet Mail Server sims.3.5.1999.09.16.21.57.p8) with ESMTP id <0FLP00DDPPVFMM@mta3.snfc21.pbi.net> for pghpcc@mail-sf1.pacbell.net; Wed, 24 Nov 1999 09:28:28 -0800 (PST) Received: from portal.stvinc.com by wodc7mr0.ffx.ops.us.uu.net with SMTP (peer crosschecked as: [63.75.14.242]) id QQhqsz25161; Wed, 24 Nov 1999 17:28:46 +0000 (GMT) Received: from notes.stvinc.com by portal.stvinc.com via smtpd (for [199.171.54.114]) with SMTP; Wed, 24 Nov 1999 17:19:24 +0000 (UT) Date: Wed, 24 Nov 1999 11:47:08 -0500 Subject: Re:FW: PCC Controllers To: billvigrass@hillintl.com Cc: pgcraig@bechtel.com, pghpcc@pacbell.net Message-id: <OFFC9739B0.8BB41295-ON85256833.005FE89C@stvinc.com> MIME-version: 1.0 Content-type: text/plain; charset=us-ascii X-MIMETrack: Serialize by Router on Notes/STV(Release 5.0.1|July 16, 1999) at 11/24/99 12:27:35 PM X-Priority: 3 (Normal) The post-war (and it would take some research to see if no pre-war, and all post-war cars fit this description) cars had two reistance-running points. All cars had the switching notch where the resistance was kept in until the thermostat killed power because things were getting too hot. In addition, post-war cars would revert to (or hold to) a resistance running notch with full field good for about 20 mph with the pedal part way down, the idea being to provide a way of runnng in traffic without cycling power. Beyond that point you go into the constant acceleration mode where you get to full speed. With chopper controls, as on the Kawasakis, the pedal position is both rate and speed, so if you back off to a lower pedal position you hold that speed, and to get full speed the pedal has to be all the way down. A down side of this approach is that on slippery rail you have to keep gradually pushing the pedal down to move the speed up so as to avoid wheel spin. On r.t. cars, such as N-5, the idea is to get up to speed on bad rail without asking for full rate, so the master controller notches do not represent speed, only rate. In compensation, on N-5, if you back down the control to P2, (1 mphps) you lock in the speed in a cruise control mode. (this is similar to the way the PCM and PC controls responded on the 80s' and Bullets) On Market-Frankford, the train will be automatically be governed by what the cab signal allows, so there was no need for that feature. Without poring through the schematics of each car type, it's hard to have a definite opinion about some of the experiences related below. Properties could get the cars with differences of this kind if they chose to, and might decide to do it differently the next time. Some PRCO cars (all?) had slip relays, which some (most?) properties elected not to get, for example. regards, Russ J. ____________________Reply Separator____________________ Subject: FW: PCC Controllers Author: "Vigrass, Bill" <billvigrass@hillintl.com> Date: 11/4/99 8:46 AM -----Original Message----- From: Jim Holland [mailto:pghpcc@pacbell.net] Sent: Thursday, November 04, 1999 8:34 AM To: pittsburgh-railways@dementia.org Subject: PCC Controllers Greetings! This question is mainly intended for Dr. Fred Schneider, III! My understanding of a description of the controller for the PCC cars is that the motorman is just choosing acceleration rate when he depresses the power pedal, not speed. At any depression of the power pedal the car would theoretically get to full speed if left in that position long enough. Yet in actual practice, it seems that only the all-electric PCCs operated this way, but not a-l-l all-electrics (the St. Louis cars come to mind and the ex-St. Louis cars used in SF as well as the SF double ended torpedoes, 1006-1015.) I remember riding PRCo PCC 100 (M11) as a stow-away on a PERC or PRMA charter back in the 50s. If the motorman had the pedal to the floor and then backed off to half-way depressed, the car would slow down. But if the same was done on a 17, the car would not slow down but would continue accelerating but only at a slower rate of acceleration. I noticed that the 10s, 11s, 12s, 14s, and 15s also acted like 100 - the cars would slow down as the power pedal was released. The 16s seemed to be in a class by themselves - they were a blend of air- and all-electric car features with extended range dynamics and a different controller package. If the power had been floored and the car had accelerated to about 25 mph and then the power pedal was backed off half way, I *think* the car maintained speed and might have continued accelerating. But if the power pedal was only halfway depressed after a full stop, the car would not accelerate to full speed. I remember riding a 16 home from town. As we entered the tunnel, the motorman depressed the power about 1/2 to 2/3 and the car was gently clicking off the rail joints. About a quarter of the way up through the tunnel, the motorman put it to the floor and that 16 took off like a pig stuck with a hot poker and it sounded like the speed doubled as the car really clicked off the rail joints! The 16 city cars seemed much more powerful and swift than the other cars, even the 17s. Also, on the 16s, if the pedal was kept to the floor, the power would cut at full speed. The motorman would have to release the power, allow the car to slow, and then reapply. On the 17s, the motorman could keep the pedal to the floor and when the car slowed sufficiently (to about 38-39 mph) the power would cut back in. James B. Holland ------- -- --------- Pittsburgh Railways Company (PRCo), June of 1949 -- June of 1953 To e-mail *off-list,* please click here: mailto:pghpcc@pacbell.net N.M.R.A. Life member #2190; http://www.mcs.net:80/~weyand/nmra/ ]