This new topic is related to the question about TCS on the Amtrak Chicago-Detroit line that is supposed to have 110 mph running. The FRA has continued in effect the basic 1948 ICC commands requiring automatic train stop (intermittent) or continuous cab signals for all tracks where train speeds over 79 mph are allowed. Continuous cab signals must read more blocks ahead than is the distance needed to stop a train at the maximum speed authorized for that section of track. This is a fancy way of saying the following block signal idea works only if trains have sufficient warning before they overtake something slower or fouling the track. Intermittent automatic train stop simply forces the engineer to do what the signal at hand tells him to do--e.g., STOP if the block signal is red. There should be another way of allowing 79-mph-plus running on track seldom used by freight traffic. Rather than having automatic block signals every mile or so for following trains (permissive blocks), use old-fashioned absolute manual blocks. The distant signal could be more than 120 mph stopping distance ahead of the home signal. So long as the distant and home signal had automatic train stop which would activate if the engineer did not slow down at the distant signal to whatever the stopping distance was from the distant signal to the home signal, the train could operate way over that speed in the portion of the block from the home signal in the rear to the distant signal coming up. That distance could be many miles in some cases. Hence, trains could operate at high speeds most of the time, but would have to slow to, say 79 mph, from distant to home signal. 15 to 20 miles at 110 mph or more, then 2 miles at 79 mph, then the next 15 or 20 at a higher speed could result in much faster overall running. This kind of automatic train stop would be much cheaper when coupled with very long blocks between home signals than the fancier train controls needed for high density high speed running. If the proposed midwest high speed service--a sort of resurrected Big Four Route--gets going, it will probably have track that neither CSX , NS, nor CN will be using for significant freight service. A federal statute immunizing that kind of interstate commerce facility--i.e., high speed passenger rail-- from liability to people on the tracks in the path of trains would induce states and local governments to take some serious action about fencing, reducing grade crossings, and prosecuting trespassers. After all, we seldom see a bunch of fools lollygagging on interstate highways. High speed passenger rail needs the same kind of legal protection.
Last item first: The highways have fewer tresspassers since they can be easily patroled by the police. Railroads are not so fortunate and it is usually unwise for civilian law enforcement to pursue violators onto railroad property, which is private. The fine for trespassing on railroad property can be your life, so that should be adequate. If not then "Oh well". Block signals can be used to convey much more info than a train ahead. Other problems such as open track switches and malfunctioning crossing signals can or are tied to the signal system. The need for cab signals at high speeds is partly due to the problem of seeing fixed signals in bad weather at such speeds. It is also a safety aspect to make up for us human engineers that can easily miss or forget the last signal. A problem with the long blocks is that if there is a glitch then the entire block must be run at restricted speed, a very tedious thing over many miles. The system you describe would be an absolute block, manual would mean no signal system at all. Absolute Block is currently used were cab signals are in effect and is provided for trains with defective cab signals. Under absolute block rules the train can proceed at up to 40 MPH prepared to stop at the next interlocking or signal if wayside block signals are still in use. Because of the previously mentioned items the speed is slower than normal. Cab signals and the associated train control equipment is by far the best way to operate. I run in territories with and without cab signal/train control and prefer the cab signal routes. Takes a lot of the stress out of operating the train.
