>Forgot another one of the idiot "expert's" claims - that the railroads had no excuse for installing the technology by now because it has existed for more than 50 years.

>Yes - there has been simpler types of train control but I think they have actually been in use for more than a century. Whether it is ATS, ATC or CCS they have been around for a long time, but they typically only enforce (continuously or intermittently) the signal indications.

Short answer: slide detection wired into block signal circuitry has been around for at least 100 years; ATS, depending on how you define it and how it operates, is about the same age; cab signals date to the mid to late 1920s.

>And to my limited knowledge, most of the systems will only stop the train if the engineer fails to take action to slow or stop the train according to signal indication, and in many cases can simply acknowledge the system and continue on the same or restricted speed depending on the situation.

The PRR MP 54s had cab signals with no speed enforcement.

>I know the New York subway system still uses a mechanical trip system to put a train in emergency that passes a red signal - I wonder how many years that system dates back?

At least back to 1900. The TTC used to/still uses a similar system.