Hot box detection system
A hot box detection system (HOA) is used to detect inadmissible heating of wheelset bearings due to defects in rail vehicles (so-called hot boxes ). Excessive heating of a wheelset bearing can lead to an axle break and subsequently to derailment of the wagon or the resulting heat and possible sparks to ignite highly flammable goods in the train and thus to a fire .
Hot box detection systems are predominantly combined with fixed brake detection systems (FBOA, in Austria FOA) within a common system, which uses the same principles to detect excessive heat build-up, e.g. B. by stuck brakes, monitor.
From a technical point of view, these are infrared sensors that are mounted in the track area and that measure the temperature of the axle bearings of the passing vehicles and transmit the measured temperature values to an electronic evaluation system. If a certain value is exceeded, a message is automatically sent to the responsible dispatcher , who takes the necessary measures for the safety of railway operations.
A combined HOA / FBOA system in Germany usually consists of three sensors. Two of these sensors represent the HOA part of the system. They are located outside the rails when viewed from the center of the track and measure the temperature of a journal bearing moving past above the sensor. If the temperature of the axle bearing exceeds a previously defined limit, an alarm message is issued. The FBOA part consists of the sensor which is mounted between the two rails on the rail sleeper. It measures the temperature of a brake moving past diagonally on the opposite side of the track. If the temperature of the wheelset bearing exceeds a previously defined limit, an alarm message is also issued, which can be triggered by "warm alarm" and "hot alarm". In contrast to the HOA, only one of the two brakes is required to be monitored with an FBOA, since, due to the nature of the system, they apply or release simultaneously on both sides of the wheelset.
In the international environment, there are now systems with up to 8 sensors, which can flexibly monitor different positions of wheel set bearings or different types of brakes or map monitoring redundancies.
The specification of hot box detection systems is carried out in Europe by DIN EN 15437-1 and by the TSI .
In order for hot runners and firm brakes on a rail vehicle to be reliably detected, their axles must also be designed in accordance with the specified specifications.
Several makes of HOA were tested at the Deutsche Bundesbahn between 1964 and 1969. Building on these test facilities, 54 HOAs were put into operation in an initial stage in 1969. Based on the experience gained, the implementation of a second expansion stage began in 1978. There are around 420 hot box location systems in the Deutsche Bahn network (as of 2007), and 473 on the Austrian Federal Railways .
A dissertation presented in 2014 recommends shortening the minimum distance between two hot box detection systems in the DB network from 70 to a maximum of 59 km.
Web links
- Information on HOA / FBOA
- Locations of hot box detection systems (incomplete) in OpenStreetMap
Individual evidence
- ↑ Presentation of current systems from voestalpine
- ↑ Jörg Pachnicke: Technology of the hot box location systems (HOA) for the 2nd expansion stage . In: Elsner's paperback of railway technology . 1982, ZDB -ID 242938-X , p. 153-171 .
- ^ Deutsche Bahn AG: Deutsche Bahn firmly rejects allegations from the Federal Audit Office . Press release from March 2, 2007
- ↑ ÖBB in numbers. (PDF) ÖBB, archived from the original on March 30, 2016 ; accessed on January 31, 2019 .
- ↑ Ralph Fischer: Investigations into the required safety level of hot runner and locked brake detection systems . Dresden 2015, p. 3 (PDF) ( PDF ).