Method and device for detecting a derailed state of a rail vehicle

An apparatus for detecting a derailment state of a rail vehicle, the apparatus comprising:

• a first sensor provided on a first wheelset bearing housing of a first wheelset of the rail vehicle,
• a second sensor arranged on a second wheelset bearing housing of the first wheelset;
• and
• at least one computing unit provided in or on a railcar of the rail vehicle;
• wherein the first sensor, the second sensor and the at least one computing unit are operatively interconnected;
• wherein at least one kinematic variable is measured via the first sensor with respect to a first wheelset end portion and via the second sensor with respect to a second wheelset end portion, corresponding measurement signals being formed, processed and evaluated by the at least one computing unit;
• wherein the at least one computing unit is configured to:
• calculate values of a first falling velocity with respect to the first wheelset end portion and calculate values of a second falling velocity with respect to the second wheelset end portion from the measurement signals;
• and
• detect a derailment state of the rail vehicle via a first comparison operation of the first falling velocity with a first falling velocity limit value and via the first comparison operation of the second falling velocity with a second falling velocity limit value which is greater than the first falling velocity limit value, at least when the first falling velocity is equal to or greater than the first falling velocity limit value and the second falling velocity is equal to or greater than the second falling velocity limit value;
• and
• wherein the second falling velocity limit value relates to a subsequent derailing and the first falling velocity limit value is based on an initially derailing wheel.