Skip-stop
The skip- stop or skip- stop ( German literally stop skipping, mutatis mutandis operating with alternating Hold) is a form of operation for public transport with regular service, in which the stops are operated at a range of consecutive courses in rotation. She is now best known for their use in some of the older of the United States subway systems and there is especially during rush hours to increase travel speed and transport capacity over longer distances away for use.
Originally skip- stop was widespread at the trams in the United States over a long period of time far. It was introduced at the beginning of the 20th century, when the cities grew strongly outward and thus to bridging distances have been getting bigger. In the subways Skip -stop was not introduced until after the Second World War.
Operation
In Skip -stop courses ( "traits " ) are scheduled on a given line into two groups and received a mark to distinguish them. This is done mostly by marking the car by the letters A and B. The support along the route concerned are marked in the same way, so that it can be seen that hold classes there, and what not. In this case, switch "A- holding " (A stops ) and "B - hold" (B stops ) from; the same direction transfers between train groups are along the route at regular intervals inserted " AB- holding " (AB stops ), where keeping both groups.
Outside the rush hours usually only rates are driven, which hold everywhere and are accordingly labeled with both A and B.
Instead of letters Skip -stop can also be accomplished by higher-level operation of two different lines.
Pros and Cons
The advantages of skip- stop are increasing the travel speed by a reduced number of intermediate stops and a larger transport performance by a dense sequence of moves. This is just on such routes advantageous where it comes to rush hour capacity bottlenecks that can not be solved by the construction of additional tracks. Here, not only financial, but sometimes technical reasons are decisive. For example, the elevated tracks of the New York Subway always have to make do with only three tracks, because the clearance between the fronts of the houses leaves no room for a fourth track. Thus skip- stop is often the only way to increase the transport capacity.
The disadvantages include that at certain times certain objectives can not be approached. So it is impossible to relevant times to get from an A to a B - stop - stop, without changing trains at an intermediate AB Stop with waiting time. Especially in heavy traffic between adjacent neighborhoods considerable traffic problems can occur due to transfer passengers between the two train groups. The cumbersome handling also leads to orientation problems among the passengers. Furthermore, the fact that each unserved holding be passed partly at full speed poses significant risks to passengers waiting on the platforms.
Examples
- On the Market - Frankford Line in Philadelphia Skip -stop is used since 1956, especially on the stretch north of downtown. The marking of trains and hold is effected here by the letters A and B.
- In the Chicago 'L' almost all the lines were operated with skip -stop between 1948 and the early 1990s, because the travel times by the high number of transit stops along the routes in conjunction with poorly motorized rolling in normal operation would have been too long. Due to the closure of many stations and better vehicles that journey times could be significantly reduced over time, so skip- stop was abolished in the 1990s.
- An example of skip- stop with different lines, the New York City Subway. On the BMT Jamaica Line, the lines J and Z operate in rush hour east of Myrtle Avenue station with alternating holding and off-peak time, only the line J, which then stops everywhere. A similar configuration existed from 1989 to 2005 on the IRT Broadway - Seventh Avenue Line with the lines 1 and 9