Return to train interlocking signal : LUSENET : ACL and SAL Railroads Historical Society : One Thread

I am in the process of drawing out the signal and siding layouts on the SAL Birmingham Sub. and hope some one can tell me what a return to train signal is. I have copies of blueprints of the automatic interlockings at Wellignton and Cedartown and it looks to be a single signal light in both directions and only on the Seaboard main. Also if possible the color of the indication.

-- Billy Thomason (, February 13, 2005


I am familiar with two types of return to train signals, one on the Southern Railway ( NS ) here in Gainesville, Ga., and one at the Norfolk Southern interlocking tower before the days of CTC where the Norfolk Southern crossed the doubletrack mainline of he ACL at Wilson, N.C. Here in Gainesville before yard capacity was increased by the construction of New Holland Yard north of town, set-off trains arriving at Gainesville on the No. 1 mainline always stopped and cut off south of the Gainesville Midland crossing, where they would get a high green signal to cross the Midland and come into town to set-off and pick up. With his train sitting in the block just south of the Midland crossing, there had to be a provision for the dispatcher to give him a signal to re-cross the Midland and go back to his train. The signal mast on a cantilavered signal tower over the No. 1 track southbound had three signal heads on it. The top head had three aspects, green, yellow, and red, top to bottom, and was used for straight running on the No. 1 track. The middle head had three aspects green, yellow and red, top to bottom, and was used for diverging routes at a crossover south of the Midland. The third, or bottom head had only one aspect, yellow, and that was it's only use, to permit a train to cross the Midland if there was no conflicting move, and go back to his train. Since all set-ff trains now go north of Gainesville to set-off, it has probably been years since that bottom aspect of the bottom head has been used, if ever. In Wilson, N.C. it was not unusual for a northbound freight train to cut off south of the Norfolk Southern crossing and go into town to do local work. But, he too had to re-cross the Norfolk Southern to get back to his train. Remember, this was in the days before radio. As he bqacked toward the Norfolk Southern interlocking tower he gave four blasts on the whistle to notify the operator in the tower that he wanted back across the NS crossing. Right between the tracks at the southbound home signal was a dwarf signal with only two aspects, red nd yellow. The normal position for this dwarf signal was red. If there was no conflicting move on the Norfolk Southern the tower operator would pull back on a lever that manually changed the dwarf signal from "stop" to "proceed at restricted speed" posiion, or from red to yellow. It was up to the brakeman riding the rear of the train to observe the position of this signal and either sign the engineer down, or signal him to come on back over the Norfolk Southern crossing. There was a similar situation on the south side of the NS crossing. The ACL Wilson switch engine had to regularly come down the southbound mainline south of the NS crossing in order to switch the ACL-NS interchange track. Since he too had to run against the current of traffic going back uptown to Wilson, it was necessary fr him to get a proceed signal from the dwarf signal located south of the NS crossing between the two ACL mainline tracks, and manually controlled by the tower operator. In reality, a go back to your train signal is the most restrictive signal available short of a stop signal, as it allows a train or engine to move very carefully looking out for an osstruction or an unsafe condition. I hope that I have not confused the 8issue for you.

-- Bill Sellers (, February 15, 2005.

The only return to train signal that I am aware of is the audible signal given by train whistle.

-- Willam E. Griffin, Jr. (, February 14, 2005.

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