Seems that this thread has encompassed three different technologies. PTC is only an alerter/enforcement system that is communications based as opposed to hardwired track circuit. The details of the systems may vary a bit, but the system does not have control of all aspects of the train movement. RC systems have a human with a radio control pack that selects a desired action from the onboard computer. The computer can then determine how best to meet the request. For anyone that has seen a remote control belt pack you will know that the operator can select a speed 'range' and direction, plus stop or go. This process still requires a human's input. RC operators on most railroads are not allowed to occupy the engineer's seat, or even the cab, while using the beltpack. That would defeat the purpose of not having an engineer. From my experience the RC switching operations that have had derailments appear to be from lack of ability of the RC operator to 'feel' what is going on onboard. A simple example is that when you are on the engine and a stop is required then the engineer will gradually apply the brakes until the slack comes in "you can feel it" and then increases the braking effort to stop. If an RCO calls for a stop then the computer does everything it can to comply. Slack action in any given cut of cars can vary greatly, far beyond what the RC equipment can be programmed to know. Totally automated operations have no human input. This technology exists already and is used on some transit systems and mine railroads. When I was young I witnessed a mine train someplace in the West that ran on a pre-programmed cycle, including public crossings. The train came up to a crossing, the gates and lights activated, the train horn sounded and then it started to move. If you were stupid enough to ignore the warnings then you would get hit, end of story. With human control on board at least the idiots might have a chance. Out on the open road there are far too many variables to contend with. As was mentioned previously the fully automated systems have a place in a closed environment. All the sensors and optics in the world cannot easily replace the human. If the companies would treat the humans better (better schedules/rest/etc) then I really think they could improve the operation. Fatigue or greed plays a big part in many accidents and it isn't always mentioned in the investigation. See my posts in the Hours of Service thread. PTC or cab signals are good things to help the crews do their jobs. RC and full automation are only about the $$.