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| Re: TA is obsessed with CBTC, and ''New'' tech for no reason. (579790) | |||
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Re: TA is obsessed with CBTC, and ''New'' tech for no reason. |
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Posted by Jeff H. on Mon Mar 3 03:19:39 2008, in response to Re: TA is obsessed with CBTC, and ''New'' tech for no reason., posted by Stephen Bauman on Sun Mar 2 05:58:59 2008. That's what I meant by there being an analogy to the Nyquist Sampling Theorem with accelerationtaking the place of frequency. I'm clearly viewing the wayside signals and block system as a sampled data system. I'd rather not get into a more detailed explanation involving z-transforms. I try to limit myself to high school math in my posts and quite frankly my z-transform knowledge is a bit rusty after 40 years. I know what s-z transforms are, but they are just marginally useful here. Now that you put it in terms of the samping theorem and Nyquist rates, I understand your earlier remark. BUT, what's the cost of raising the sampling rate? Plug in some numbers to your formulae. I think you'll find that in order to control speed to the same level as a continuous signal system, even allowing for enforcement delay of the latter, you would need to space signals every 100 feet, maybe less. Operators are permitted to look ahead to the next wayside signal. I believe it is encouraged. If they can see it! Curves, tunnels, etc. A downgrade on the current block after the follower has entered it suggests that the leader has crossed an IJ in the direction going towards the follower. Read what I said again, carefully. If a CONTROLLED signal is dropped. That means an interlocking or approach signal which is under tower control. |
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