Integra-Signum is a Swiss
train protection system
A train protection system is a railway technical installation to ensure safe operation in the event of human error.
Development
Train stops
The earliest systems were train stops, as still used by the New York City Subway, the Toronto subway, ...
introduced in 1933. Originally it was called Signum; the name Integra was added later. It transmits data
inductively and is simple, robust and reliable also in snow.
How it works
The locomotives have three sending and receiving
magnet
A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nicke ...
s and there are two trackside magnets near the
signals.
Integra-Signum asks the train driver to confirm distant signals that show stop and distant or home signals that show caution. If he does not confirm or passes a home signal that shows stop, the train is stopped automatically. This is achieved by interrupting the power supply to the motors and applying the emergency brake.
The locomotive's sending magnet is a strong permanent magnet, which induces a current in the receiving magnet in the middle of the track, if the signal's short-circuit contact is closed. The receiving magnet on the locomotive consists of two magnet field detectors, which detect the signal's state according to polarity and timing of the magnetic field emitted by the second magnet outside the track:
Stop (home signals): positive - negative, concurrent
Caution (distant signals): negative - positive, concurrent
Caution (home signal): positive - positive, not concurrent
Because Integra-Signum can only stop a train when it's "too late", i.e. after the red signal, it is not sufficient if there is an obstacle less than the braking distance away from the signal, which is especially a problem with fast trains. To address this issue,
Zugbeeinflussung ZUB has been introduced.
Despite that Integra-Signum aims to prevent accidents, there was also an accident caused by it. In 1959, an Integra-Signum magnet mounted on a
SBB-CFF-FFS RBe 540 EMU tore out a wooden sleeper on a level crossing near
Gland
In animals, a gland is a group of cells in an animal's body that synthesizes substances (such as hormones) for release into the bloodstream (endocrine gland) or into cavities inside the body or its outer surface (exocrine gland).
Structure
De ...
, which led to the derailment of the entire train at 125 km/h.
Phasing out
By 2017 Switzerland had almost completed the migration to ETCS Level 1.
Integra-Signum will remain in service for a few years more on a small number of special lines; one of these is the
Uetliberg railway line, which will first be converted from DC to AC electrification.
From beginning 2018, new vehicles running on the Swiss network do not need anymore the class B system SIGNUM and ZUB.
See also
*
Train protection system
A train protection system is a railway technical installation to ensure safe operation in the event of human error.
Development
Train stops
The earliest systems were train stops, as still used by the New York City Subway, the Toronto subway, ...
*
Integra Signum {{Short description, Swiss railroad company (c. 1890–1992)
Integra Signum was a publicly traded Swiss company active in train control and signaling systems. Its main achievement was the development of the train control system Integra-Signum, whi ...
, the company that developed the system
References
{{Railwaysignalling
Train protection systems
Rail infrastructure in Switzerland
1933 establishments in Switzerland