absolute block system การใช้

• This was called the " absolute block system ".
• Even with an absolute block system, multiple trains may enter a block with authorization.
• The absolute block system was in place, but was not being operated in accordance with the regulations.
• The electric telegraph provided the ability for signalmen to communicate with each other and provided the basis for the absolute block system.
• The absolute block system controls the safe movement of trains in the block section, and no more than one train may ever enter the section at once, other than in exceptional circumstances.
• The absolute block system came into use gradually during the 1850s and 1860s and became mandatory in the United Kingdom after legislation in 1889 following a number of accidents, most notably the Armagh rail disaster.
• The absolute block system does not replace the use of any other form of signalling, such as fixed signals, hand signals, or detonators ( and, in fact, usually relies on fixed signals ).
• Whereas the Absolute Block System maintains a space interval between trains to prevent collision, the Permissive Block System permits trains to follow one another into a block section without special protection other than a speed restriction, usually of 4 mph.
• The signalling operation on the southern route ( via Atherton ) prior to 2013 was by the older method of the absolute block system ( AB ) as far as Walkden High Level signal box ( a distance of around 7 miles ).
• The tragedy was heightened by the fact that the Absolute Block system which would have prevented the disaster ( by preventing more than one train from occupying a section of route at the same time ) was being installed at the time; and was due to be switched on only 10 days later.