Did CSX inherit the DTC block control method from SAL...or was it common for many dark railroads? Also, I am curious as to why CSX seems to be the only Class I that still operates some fairly busy lines using DTC rather than CTC.
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That's easy...COST!
CTC requires linseside signals, electricity in the field, expensive computer software, on-going maintenance costs for the signal system, etc. BIG bucks.
All you need for DTC is a radio, a pencil and a piece of paper.
True....but compared to NS or BNSF, UP....seems more inefficient. Some of CSX DTC lines see 20 trains per day. Albeit around here they have installed CTC islands to manage to sidings.
SP used it. KCS is using a version of it. To me it seems better than WTC because the places for the beginning and ends of warents are fixed locations.
And it works a LOT better than NS's Auto (OTTO as we call it) Router they bought from GE. If you want to watch a meltdown, watch an ATCS monitor of the CNO&TP when it's on full OTTO Mode and not DS override. Surreal.
I had a little experience with DTC when running over SP on trackage rights. I was raised on timetable and train order operation, and then Santa Fe adopted Track Warrant Control (TWC). I did not like it at first, but became friendly with it after its advantages proved themselves.
SP changed to TWC after merging.
For those unfamiliar, DTC allows use of a block with fixed limits marked by right of way signs and listed in the timetable. You can go all the way to the end of that block but no further. It only requires verbal repetition of the limits to the Dispatcher, and no paper form is required. However, a paper form may be used, if the employee so desires, completely at his discretion.
TWC uses a paper form with numbered boxes for several different types of movement and blanks for the location of the end points of main track authority. The employee has to check the box and enter the locations (making a second copy with carbon paper), and then repeat the authority verbally to the Dispatcher by radio, reading it from his completed form.
Either form of authority will work, as the results prove. Like retired Road Foreman of Engines D. Bailey would say: "Y'all got your Fords and your Chevrolets. Some favor one, and some favor the other."
