Nostalgia & History > ATS vs. ATC

I was reading an old copy of The Warbonnet (ATSF Historic group mag) and read an article about Automatic Train Stop (ATS), a system developed in the forties, or earlier, that would ensure that a restricting signal would be acknowledged with the penalty of a brake aplication if ignored. It used a trackside inductor and was installed on various locomotives, ranging from ATSF 4-6-2 Pacifics to today's F59PHI.

The article also mention an Automatic Train Control (ATC) that was in place on the eastern side of the ATSF system - but that is all that it said. How did the ATSF ATC system work? What were it's limitations? Why was ATS out west used vs ATC? ATS permits speeds in excess of 79 MPH, did ATC also alow speeds in excess of 79 MPH?

john1082 Wrote:

> The article also mention an Automatic Train
> Control (ATC) that was in place on the eastern
> side of the ATSF system - but that is all that it
> said.

If you have access to a complete set of Warbonnets, the 4th Quarter 2000 issue had an article on the ATC system used by Santa Fe in Illinois. There's been some discussion of ATS/ATC and cab signals in the recent past:

http://www.trainorders.com/discussion/read.php?1,624937
http://www.trainorders.com/discussion/read.php?1,623308

I wish I had access to a Warbonnets collection. Those are great links that explore the installation and workings of ATS. Still no clue, though, why ATSF had ATC in the Chicago vicinity early on. The installation of ATS out west makes perfect sense, but why ATC in the east?

john1082 Wrote:

> Still no clue, though, why ATSF had ATC in the Chicago vicinity
> early on. The installation of ATS out west makes
> perfect sense, but why ATC in the east?

The two installations were due to ICC orders two decades apart, and the use of the different systems was probably a reflection of their different cost and the extent of their installation. The ATC installation came first, in response to two ICC orders in 1922 and 1924 requiring railroads to install ATS, ATC, or cab signals in conjunction with an automatic block system on one "engine district." Santa Fe installed US&S continuous three speed ATC with cab signals between Pequot and Niota, IL, with the whole system in place and operational by 1927.

The second ICC order came in 1947 and had a much greater impact. It required railroads to install ATS, ATC, or cab signals in conjunction with an automatic block system on *any* line where trains operated faster than 79 mph. Speed was important to the Santa Fe, but the ATC system in use in Illinois was much more expensive and complicated than the ATS system US&S had available. ATS also had the benefit that a non-ATS-equipped locomotive could lead a train in ATS territory so long as its train did not exceed 79 mph, as ATS routes had full wayside signaling. In ATC territory, wayside signals were only present at interlockings, so all lead locomotives had to be equipped with the elaborate ATC/cab signal equipment. To comply with the 1947 ICC order, Santa Fe would ultimately have to equip more than 10 times as many miles of track with train control as they had for the 1920's orders (nearly 3000 miles of main line versus less than 200 miles). They opted for the less expensive system and went with ATS.

Santa Fe ultimately installed CTC in Illinois and removed the ATC system in 1970. After the coming of Amtrak, they also removed ATS from lines where passenger trains no longer ran.

That answer was right on the money. Thanks.

I know that ATS came off various districts when passenger traffic came off. I suspect that we've seen all the ATS trackage that we are going to see. Former ATSF lines have it but I doubt that there is much of it outside of the former ATSF lines. It is neat, though, to see photos of old ATSF steamers carrying the same receiver shoe that is mounted on the F59PHI that will cary me to LA this week.

Just for kicks, here's a bit of classic Santa Fe signaling. We're at Pauline, KS on the line from Emporia to Topeka in 1990. The ATS inductor is that silver thing next to the inside rail.

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john1082 Wrote:
-------------------------------------------------------
How did the ATSF ATC system work? What
> were it's limitations?

Santa Fe's ATC was used only on the Illinois Division between Peqout and Niota. It was installed in response to the I.C.C Order of 1921 which required all railroads to install some form of the then-new train control systems on at least one division. Santa Fe selected Union Switch & Signal Co's ATC which was installed by 1927. A key feature of the system is that there were no wayside signals except at interlockings and all lead locomotives (both freight and passenger) needed to be ATC-equipped with cab signals. By the 1960's, the system had become unreliable. Further, Santa Fe wanted to end the inflexible practice of having a dedicated class of ATC freight units to serve as leaders east of Ft Madison, IA. 2MT CTC was the answer, and it was cut over in October, 1970. Passenger train speeds were reduced from 90 to 79 mph.

Why was ATS out west used
> vs ATC?

Cost, flexibility and reliability. The I.C.C. Order of 1947 hit AT&SF hard. Traditionally and conceptually, ATC was encorporated on all classes of trains, freight and passenger, division-wide, with or without wayside signals. Santa Fe did not want to equip 1000+ freight units with ATC (which would not exceed 79 mph)at a cost of $10K each in 1950 dollars. Also, ATC systems of the day were notoriously unreliable; ATS is a much simpler, more reliable technology. Finally, Santa Fe only wanted to install ATS in selected "flatland" territories carded for passenger train speeds in excess of 80 mph. Accordingly, the AT&SF successfully petitioned the I.C.C. to install ATS only in certain 79+ mph territories on the Ft Mad-La Junta-Calif and Newton, KS-Texas mainlines and only passenger engines were equipped. Santa Fe had until October, 1952 to comply with the order, but most ATS was installed in 1950-1951. Somewhat wastefully, ATS was installed on dozens of passenger steam engines even though all passenger services were dieselized by 1953. I always thought it ironic that the government forced the railroads to spend millions of dollars on supplemental signal devices, which were then property-taxed, but provided the waterway and airway industries their safety/navigation systems for free.

ATS permits speeds in excess of 79 MPH,
> did ATC also alow speeds in excess of 79 MPH?

Yes, neither system had an inherent speed limit. The ATC Illinois Division had a timetable psgr speed of 90 mph, whereas, ATS zones west of Hutchinson, KS initially had a speed of 100 mph. As any fan of Santa Fe passenger trains will tell you, a speed limit in ATS/ATC territory was an arbitrary concept, especially if a train was late. Bob

Plenty of those inductors on the Surf line. In fact, there used to be one along Lincoln Avenue in Santa Ana. Speed was closer to 45 mph there, but it was very close to the station in Santa Ana and a curve just beyond.

Evan_Werkema Wrote:
-------------------------------------------------------
> Just for kicks, here's a bit of classic Santa Fe
> signaling. We're at Pauline, KS on the line from
> Emporia to Topeka in 1990. The ATS inductor is
> that silver thing next to the inside rail.

bnsfbob Wrote:

> Santa Fe's ATC was used only on the Illinois
> Division between Peqout and Niota. It was
> installed in response to the I.C.C Order of 1921
> which required all railroads to install some form
> of the then-new train control systems on at least
> one division. Santa Fe selected Union Switch &
> Signal Co. ATC which was installed by 1927. A key
> feature of the system is that there were no
> wayside signals except at interlockings and all
> lead locomotives (both freight and passenger)
> needed to be ATC-equipped.

The Warbonnet article mentions the train control
boxes on steam and diesels like the GP20's,
but how did the ATC system manifest itself along
the right of way? "Blocks" were initially less
than a mile long - what sorts of devices were
present at the ends of each block?

Evan_Werkema Wrote:
-------------------------------------------------------
> bnsfbob Wrote:

> The Warbonnet article mentions the train control
> boxes on steam and diesels like the GP20's,
> but how did the ATC system manifest itself along
> the right of way? "Blocks" were initially less
> than a mile long - what sorts of devices were
> present at the ends of each block?

There were U.S.& S. signal cases, pole line feeds or other enclosures, wayside as needed. One signal box could relay code or DC covering multiple blocks via the pole line.

Maybe signal expert, BC Hellman, will post a reply.

Great photo and info, BTW. Bob