By Fred Westing, Mike Bezilla and Roger L. Keyser


Compiled by Chuck Blardone

Issue of 4/25/02

Page 8: The PRR’s first installation of a train control/cab signal system was the result of a PRR initiative. Working with Union Switch and Signal Co., the PRR installed a "track and loop" continuous train control system with three-speed control and three cab signal indications. This system was installed between Sunbury and Lewistown on a now abandoned branch that ran between Selinsgrove Jct. and Lewistown. Thirteen locomotives were equipped with train control and cab signal apparatus. This was the first installation where cab signals were used in lieu of wayside signals. This installation was placed in service on July 11, 1923. The signal power frequency was 60 hz commercial frequency.

On June 13, 1922, the ICC issued its first order requiring major railroads to install a form of train control/cab signals/train stop on one passenger locomotive division. In response to this order, the PRR petitioned the ICC for a delay in the implementation until it could finish the above mentioned test installation. The first cab signal/train control installation on the PRR proper in response to the ICC order was on the ex-Northern Central line between Baltimore and Harrisburg. This installation used the track and loop system with three speeds and three cab signal indications. It was placed in service on July 17, 1926, and it was the first use of 100 hz as the signal power frequency.

The first coded cab signal/train control system with four indications was placed in service on March 20, 1927 on the PRR owned West Jersey & Seashore, between Atlantic City and Camden.

The ICC issued a second train control system order on January 14, 1924, mandating an installation of some form of train control on a second passenger carrying division. PRR chose to install a coded four-indication cab signal/train control system between Harrisburg and Altoona.

Starting in 1930, in conjunction with its AC electrification efforts, the PRR started to install cab signals only without brake applying apparatus. In 1933, the PRR successfully petitioned the ICC for permission to remove train control/train braking apparatus from its previous installations. Therefore, not a single PRR electric locomotive was fitted with any means of train control or train braking connected with the cab signal system in the period 1930-1951. In fact, the only PRR locomotives that had any type of train stop equipment were those units assigned to Erie Pa., where they were fitted with NYC type Intermittent Inductive Train stop to permit them to operate on NYC trackage rights between Girard Jct. and Erie!

After a series of accidents where the cab signal was acknowledged but speed was not reduced, the PRR in 1951 placed a $10,000,000 order with Union Switch & Signal Co. to equip 307 passenger locomotives with automatic train control that was tied into the cab signal system. Extensive wayside system modifications were also made. Since this order covered passenger power, it is unclear if the P5 units were eventually fitted with train control after 1951.

The coded cab signal system interrupted the signal power in terms of interruptions per minute, while the signal power and commercial power frequencies were rated on cycles per second. There was no correlation between the frequency and its harmonics and the code interruption rate. 100 hz was chosen because it was a frequency that was immune from being influenced by 60 hz commercial power. Other railroads used 60 hz signal power with coded track circuits.

The PRR did experience problems with 100 hz track circuits in areas such as the N.Y. Terminal, where it ran both A.C. and D.C. electrifications simultaneously. D.C. power was originally obtained from 25 hz power and a fourth harmonic at 100 hz was found to influence the 100 hz track circuits. The PRR used 91-2/3 hz in those areas as the signal power frequency.

Page 9: In "Altoona Test Summary," item 6, line 8, "…must take place to remove the salts being constantly contained by the feedwater…"

Page 11: The Chassis Diagram captioned for P5A shows a GG1.

Page 48: The captions for the P5 (# 4700) and P5B (# 4702) have been interchanged.

Page 51: In "P5 Specifications," Timkin should be Timken.

Page 54: The photo captions for # 4752 (lower left) and # 4745 (upper right) are reversed.

Page 55: In the third paragraph, …72" diameter drivers, equal in size to those of the K4s…" No so. The K4s had 80" drivers.

Page 64: Right hand column, beginning of the 5th paragraph, should read: "A crossover switch…"

Page 78: Right hand column. Signal L-309 name should be Approach (not Stop Approach).

Page 84: Lower right photo – should be Tom Harley, not Hartley.

Page 88: The second unit involved in the collision was # 4772 (not 4775). The error appears both in the photo caption and in the text.

Page 93: The caption for the center right photo of 5800 should read DD2…, not DD1…"

Page 98: The lower left photo caption "FF2 # 5017---" should read "FF2 # 7…"

Page 109: The "Built Date" for E44 # 4400 is incorrect. # 4400 arrived at Enola for test in October of 1960, while I was working at the engine house. She was under the control of GE Service and Installation people from Erie, led by Bill Kirkland. I took pictures of her in the area at that time. Yesterday, while checking some details for my Camp Hill P5 effort in May, I found, in my notebook of those days, that she was called for her first revenue service at 4:40 p.m. (on my trick) for a "Lancaster Turn," on December 28, 1960. I suspect that the December 27 date is the date she was "accepted" by the railroad. Edson’s book and other sources have the "Built Date" as "10/60," which would seem to be correct. The "Built Dates" for other E44 appear to be okay, but they may also be the date the railroad accepted them, rather than the dates on their badge plates, which usually showed only the month and year of their construction without a specific day. However, after the first unit was accepted, there was little delay for testing and the acceptance dates were almost the same as the delivery dates which closely followed the completion of construction.

Page 110: The "Built Date" for FF2 #7 (ex-GN #5017) should be 7/30 not 3/30. Edson’s book also has the incorrect date. I have the badge plate, which is clearly stenciled "JULY 1930."

[Thanks to Michael Savchak, Bill Volkmer, Robert B. Watson and Frank Wisegarver for the above.]

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Last Updated: October 28, 2008

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