I-ETMS Question - Please help

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Steve McEvoy

New Member
I am a rail transportation engineer working for a commuter railroad that will be using ACSES.

I have a few simple questions about I-ETMS and am hoping that there are some BNSF engineers or other knowledgeable railroaders on here who can answer these questions.

1 - Does I-ETMS monitor or control throttle setting or propulsion power? Does I-ETMS ever take propulsion power away, and if yes, how quickly and under what conditions?

2 - Does I-ETMS permit bail-off of the engine brake(s). I am assuming that I-ETMS permits bailing off the engine brake as long as the train stays below the governing profile!? Does I-ETMS ever prevent engine-brake bail-off, and if yes, under what conditions?

E-mail answers will be fine, and a telephone call will also be fine.

Thanks in advance.

Steve McEvoy

AECOM (Ex New Haven, Penn Central and LIRR railroads)




I-ETMS monitors the throttle position. I-ETMS' only response/control it to place a train into penalty brake, or under some cases emergency braking.

Steve McEvoy

New Member
Thanks Crow.

So, I-ETMS never directly changes propulsion power.

In the case of a penalty or emergency brake application, does the locomotive on-board equipment do anything to automatically remove propulsion power?

As you can tell, I am trying to determine what if anything I-ETMS directly or indirectly does to take away propulsion power. If it does nothing, I assume the only thing that takes away propulsion power is the engineer manually moving the throttle!?

I still have the questions about the engine-brake bail-off.

As I said, I am working for a commuter railroad designing the ACSES PTC overlay on ATC cab signaling, and I am also charged with designing freight-train field braking tests.

My concern about propulsion power is if it is not automatically removed in some manner, directly or indirectly, worst-case braking distances can increase.

If you want to call me and confidentially chat, that would be great. If you are not a locomotive engineer, please feel free to refer me to someone who is.

Steve McEvoy
Office phone - 610-399-3412
Eastern Time Zone

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