Pass Track Arrangements on the ACL Double Track Mainlinegreenspun.com : LUSENET : ACL and SAL Railroads Historical Society : One Thread
More "nuts & bolts" type questions. When originally doubletracked in the 1920s, the pass tracks on the ACL mainline were placed in the center between the north and south bound mainlines. Later in the 1940s, many of pass tracks were relocated from the center to the outside of either the north or south bound mainline. Does anyone know the rational behind this relocation?
When using a center pass track configuration, what type of switch stand was used for the center pass track where the route diverged to rejoin both the north and south bound mainlines. Photos from the 1930's-40's indicate the ACL used the "high" styled RAMPCO switch stands for the mainline switches leading to the passing siding. I've been unable to locate photos of the sitch stand for the center pass track.
Photos from my hometown indicate that "Take Siding" indicators were mounted on the semaphores before the entrance to the pass tracks. Was this always the case?
Finally, in my hometown during the height of the produce season the pass track was used to store empty reefers until they could be moved onto the branchline for loading. Does anyone know if using the pass track for car storage was common practice elsewhere on the system and if so, how big an operational headache it was for dispatchers to move trains across the system? Thanks for your patience and any answers.
-- Buddy Hill (palmettoLTD@hotmail.com), September 09, 2001
Buddy: The ACL engaged in a major track improvement/signal improvement program in the immediate post war period to address several issues. A majority of the existing main line was laid with 100 lb rail which was exhibiting an excessive number of failures resulting in some very serious accidents, including the Buie and Stockton disasters. The replacement of this rail with 131 lb rail was a priority. While this work was being performed, portions of the track were realigned to minimize rail wear, and the removal of the center track passing sidings was part of that program. Signals were being respaced to permit higher speed operations and the respacing was based upon braking rates from speeds of 100 mph. However, posted 100 mph train speeds only occured for a very short time period in the mid 1950's. This was due to the fact that before the ACL could finish the respacing of the signals, the ICC issued an order on June 17, 1947 limiting passenger train speeds to 79 mph unless cab signals, train control or train stop was in service. The ACL had train stop in place only between Richmond and Florence at that time. At that time, maximum speeds for diesel powered trains were 80 mph, and 75 mph for trains led by P-5A and P-5B locomotives. All other trains were limited to 70 mph. ACL started to install train stop south of Florence but work proceeded slowly and was only completed as far south as Waycross by 1957. The passenger only Jesup-Folkston cutoff never had train stop installed, nor did the line south to Jacksonville. 100 mph train operation was established for a few of the top trains in 1955, but lasted for a limited time and soon, the maximum train speed was 90 mph in train stop territoty. this lasted until 1970 when the train stop was removed.
-- Michael W. Savchak (Savchak@mnr.org), April 03, 2002.
Finally found the answer to my intial question in an article on the ACL's postwar rehabilitation of its physical plant. The article states that the ACL relocated many of the center pass tracks to the "outside" of either the NB and SB tracks in order to straighten the mainline. Imagine this resulted in a smoother ride for the 100+mph passenger trains common in the late 40s.
-- Buddy Hill (palmettoLTD@hotmail.com), April 02, 2002.
Buddy - I failed to note that Weldon Yard (south of the Roanoke River viaduct) also had a center siding. Because the operator at Weldon Yard controlled the crotch switch at south end of the center siding, I suspect that was controlled by a switch machine and a dwarf signal.
N&W also made use of center sidings (called middle tracks on N&W). N&W's Book of Standard Plans indicates that the Ramapo model 20-C (about 24" high) would be used on double track where necessary to locate it between the main tracks OR where clearance was a factor. Didn't know it, but the New Century type switch stand was restricted to use in yard and secondary tracks. Guess the Ramapo switch stand was the premium model.
-- Harry Bundy (Y6B@aol.com), September 18, 2001.
Thanks for your thoughts and the information. Do you recall the style of the switching mechanism used to activate the crotch switch - a low "ground throw" style switch or the same high switch stand used for the mainline switches leading to the crotch switch? Thanks again.
-- Buddy Hill (palmettoLTD@hotmail.com), September 11, 2001.
Buddy: I can't explain ACL's rationale for moving the passing sidings to the outside of the main tracks. The 1953 ACL track profile shows ACL still had middle tracks at Trego, Natal, Pee Dee (north end of Pee Dee River single track),St. Stephens (south end of Santee River single), Chatham (Savannah River single) and Doctortown (south end of Altamaha River single), so maybe ACL retained the middle track configuration where grades (Natal) and single-track river crossings were involved.
Reefers on the passing sidings -- the dispatcher will usually issue a bulletin order indicating that a siding is blocked with cars. That puts the onus on the train crew to arrange an alternate siding to clear the time of a superior train.
The turnout which leads from the center siding to the north and southbound main tracks is referred to as a "crotch switch".
-- Harry Bundy (Y6B@aol.com), September 10, 2001.