manual block system造句

Manual block systems work by dividing up a rail line into predefined " blocks ", which are typically demarcated by fixed signs.
This manual block system is still on use on the Long Island Rail Road, which had been a subsidiary of the PRR.
Bi-directional ABS was popular on lower density single track lines that nevertheless needed an upgrade from older train order or manual block systems.
A manual block system in the United States was implemented by the Pennsylvania Railroad about 1863, a couple of decades before other American railroads began using it.
Aside from increased capacity and safety compared to a manual block system, another advantage of the single direction ABS system is that it is relatively inexpensive to install and operate, each signaling point requiring only one relay for its own track circuit and one additional relay for each block in its control length.
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