Amplifier (traffic)
As amplifiers - also amplifier output, amplifier course, amplifier trip, amplifier train, amplifier train, reinforcement car, amplifier bus or compression train - relief trips or electric cars are referred to in local public transport that take place outside of the normal regular traffic and condense the timetable offer. This usually takes place during rush hour (HVZ), i.e. in rush hour traffic or school traffic . If the reinforcement trips are given their own line designation, one also speaks of a reinforcement line, reinforcement line, operational line, relief line, supplementary line, insertion line or additional line .
General examples
For example, on a line that runs every 20 minutes, you can add amplifiers by having two vehicles instead of one vehicle at certain times; by a second following each vehicle a short time later; or by temporarily reducing the cycle to ten minutes. In general, a distinction is made between several types of reinforcement lines:
- Reinforcement lines that are shortened at both ends of their trunk line (trunk line A – B – C – D, reinforcement line only B – C)
- Reinforcement lines that are only shortened at one end of their trunk line (trunk line A – B – C – D, reinforcement line only A – B – C)
- Repeater lines that supplement several main lines and thus offer direct connections during rush hour, which require a change outside of rush hour (main line 1: A – BC, main line 2: D – B – E, repeater line: A – B – E)
- Reinforcement lines that only run in the load direction and return to the starting point in the opposite direction as an empty run in order to be able to start again there more quickly and thus save trips
- Repeater lines that serve areas that have no connection to local public transport during off-peak hours, for example industrial areas
A special form of the repeater line are main lines that go beyond their main line at one or both ends of the line during rush hour and thus serve as repeater lines for other main lines in this peripheral section.
Concrete examples
Separate lines that only run during the morning rush hour, i.e. when business and school traffic meet, but are not offered at lunchtime or in the afternoon, are rare. examples for this are
- Line 67 of the Bonn Stadtbahn (as of 2016),
- line 14 of the Salzburg trolleybus (as of 2016),
- Line 12 of the Dresden tram (between 1995 and 1999)
- Line 24 of the Prague tram (as of 2019)
In this case, some passengers who benefit from a direct connection in the morning have to change trains in the afternoon .
Another variant are lines that only run in the winter months when, due to the bad weather, fewer people tend to walk or cycle. An example of this is line 5E of the Kassel tram , which only runs in the cold season. The Vienna tram used to have special Sunday lines that were used exclusively for the busy weekend excursion traffic at the time. Another special form are the so-called All Saints' Day Lines, which are only used in heavy cemetery traffic on November 1st.
Labelling
Many transport companies mark their amplifier services differently from the usual scheduled trips. For example , as a line- independent electric car , as a line-bound electric car, with a crossed line signal or with a red line number . In Linz, reinforcement lines are marked with an additional asterisk, in Hamburg a white point on a black background was previously used for this purpose - this either supplemented or completely replaced the line number.