Western Railroad Discussion > ATS on the Southwest Chief

The Southwest Chief can run 90 miles per hour at in certain locations on the ex-Santa Fe tracks between Chicago and Los Angeles. I think they use a system called ATS. Does anybody have any details on this system? How does it work? Any information would be appreciated.

Kevin

ATS, Automatic Train Stop on the Santa Fe is a system that is limited to passenger trains operating at speeds above 79 mph. Maybe someone else can quote FRA regulations. You can track the territories requiring the use of ATS if you have a complete set of employee timetables. There is a column to the right of staions listed called "Type of Oper." It will show CTC or ABS or TWC. It will also show ATS. You will also note that below that area is the Rule 1(B) Speed: It will Show a seperate column for Passenger trains and for various stretches of track will be either 79 or 90mph. So that is how you can determine the ATS territory.
The folowing is an attempt to explain in my own terms from experience some years ago:
It is basically a fairly low tech device that could be mounted on the side of the journal box on the side frame of the lead truck of the controlling or lead loco. It is a electro magnetic sensor that is activated by a metal box, "inductor", implanted next to the ties at important locations where alertness is essential. Sometimes every signal or ahead of draw bridges or permanent speed restrictions for curves, etc. However, depending on the signal indication (i.e. green) the inductor may not activate the system. When you are out watching trains in ATS territory you can see these boxes or inductors at various locations. The bracket on the loco is a square U shape yoke with a cable into the cab.
The act of the loco passing over the track side box creates an induction current that activates a cicuit in the controlling loco that requires the engineer to acknowledge the a bell that goes off "DING" like that. There is a lever that the engineer acknowledges this Ding with. It has been quite a long time since working passenger so there may be some more modern devises on Amtrak locos.
If the engineer fails to acknowledge the ding the system is conected to the train air brake system electro-pnuematically to take control of the brakes and go into penalty application or I beleive full service application of the train's brakes to bring it to a stop. I could be wrong on this point as it could dump the air in emergency application.
Fortunately we never had to deal with an ATS penalty application. This end of the Santa Fe had a more advanced system installed in the 1920s called ATC, Automatic Train Control. That requires that any loco operating over the territory be equipped with cab signals and induction coils mounted over the rails. Sadly it was removed in 1970 therfore reducing passenger speed from 90 to 79mph from Ft Madison to Chicago.
That is why the 90 mph starts at Ft Madison going west off and on all the way west over the route of the Southwest Chief including the long fast running stretches from La Junta to Trinidad, CO. Further west on the Needles Sub-division there is no ATS according to my 4/16/95 time-table. But it does show 90 mph permitted within TWC, ABS, DT territory. So there may be special instructions in effect to establish absolute block ahead of the Chief to run 90mph or by Track Warrent in place of ATS? From Barstow west to LA the top speed is 79 mph with no ATS.
Have fun and watch out for those 90 mph trains! IG

ATS equipped motive power with the necessary "shoes" pick up a electromagneticly triggered brake application if the loco passes restrictive signals w/o proper application by engineer. Inductors are also installed on or near track adjacent to signals involved. "Surf Line" in So.Cal is one so equipped, permitting 90mph in certain stretches.

The way the rules are (Fed):
49-59 MPH dark territory, trainorder.
79 MPH Train Order, automatic block signals
90 Same as above but with Automatic Train Stop
110 The same as above but with cab signals.

The old style (early steam) was if you didn't acknowledge a signal by hitting an air valve, a rod would stick up from the ground and trip an air valve that would stop the train. You had to go back to the tender and reset this valve from the ground. Later, there was a magnet on the ground and a contact shoe on the engine truck. Now most off it is done by cycles generated through the rails. The pick up shoes are just ahead of the lead truck. It reads what the signals are and what you should be doing. If you don't comply, it sets the air and you have to stop and reset the brake valve to proceed.

If you have a UP unit on the old SP tracks, you have to watch out for electric switch heaters in the mountain areas. If the cab signals are not cut all the way out, the peanut whistle would go off, and you would have to cut out the brake pipe to reset the PC. Not quit by the rules but it beats stopping a 9,000 ton train on a grade because of a malfunction.

spnudge wrote:

> The old style (early steam) was if you didn't acknowledge a
> signal by hitting an air valve, a rod would stick up from the
> ground and trip an air valve that would stop the train. You had
> to go back to the tender and reset this valve from the ground.
> Later, there was a magnet on the ground and a contact shoe on
> the engine truck. Now most off it is done by cycles generated
> through the rails. The pick up shoes are just ahead of the lead
> truck. It reads what the signals are and what you should be
> doing. If you don't comply, it sets the air and you have to
> stop and reset the brake valve to proceed.

I think what you are describing there is ATC, Automatic Train
Control. ATS, at least as employed on the Santa Fe, is more
primitive. There is no continuous signal from the rails, only
the occasional lineside induction shoes railscenes mentioned.
And the pickup shoes on the locomotives are mounted on one of
the journals on the engineer's side of the locomotive.

In the beginning, there were no speed limits imposed by the government. It was up to each road to determine their own speed.

Then 1922 the ICC handed down an edict to all class 1 railroads that one division within each railroad had to be equipped with Automatic Train Control by 1927. Each railroad was free to choose which division would get the installation. How the ICC came to this decision I am uncertain. The Santa Fe elected to install theirs between Chicago and Fort Madison. The installation also had cab signals. The Espee installed theirs between Oakland and Fresno on the West Side Line, which was removed between Tracy and Fresno in 1933. But still, the railroads had no government-imposed speed limits.

In 1947 a devastating rear-end collision between two CB&Q passenger trains resulted in a 1949 ICC decision that imposed speed restrictions on railroads not equipped with certain signal apperatus.

1. 49mph for freight in dark territory (no signals)

2. 59mph for passenger in dark territory.

3. 79mph for passenger and freight in signalled territory.

4. No limits for freight or passenger with any form of automatic train stop or control (ATS or ATC).

The Santa Fe, who had the most to loose with this order since a good deal of their mainline was rated above 79mph, and only one district with ATC, requested a waiver from the ICC. They were ultimately denied. Now faced with a massive investment in signaling amidst declining revenue, the AT&SF elected to install ATS, the simplest and cheapest form of train control available at the time,(whose operation is described in other posts), and in territory deem suitable. The SP, which also had long stretches of 80mph or above, elected not to install the equipment, and dropped their limits.

The ICC did modify some of the restrictions. For example, in dark territory if two stations can establish Absolute Manual Block, then a freight can proceed at 59mph. The SP would do this occasionally between Hiland and Palmdale on the cut-off before CTC in 1979.

In one other note, the BNSF has dropped the speed to 79mph from 90mph in ATS territory in jointed rail territory. So, La Junta to Trinidad is 79mph.