| CPC B66B 5/0025 (2013.01) [B66B 1/3461 (2013.01); B66B 7/046 (2013.01); G01D 5/145 (2013.01)] | 14 Claims |

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1. A method for determining a degraded guide rail condition in an elevator system, comprising:
operating the elevator system, the elevator system including:
a hoisting motor including a motor encoder;
an elevator cart; and
an elevator component arranged to move relative to a guide rail, wherein the guide rail includes at least partly along a length thereof, position markings, and wherein the elevator component is arranged to move in contact with the guide rail and includes a rotary encoder for measuring movement of the elevator component relative to the guide rail, and a reader device for reading the position markings;
obtaining, by the rotary encode and the reader device, first data including information about movement of the elevator component relative to the guide rail;
obtaining, by a motor encoder, second data including information about movement of the elevator component relative to a hoistway of the elevator system;
comparing the first data and the second data, or characteristics based on said first and second data to each other;
detecting, based on the comparison, a deviation fulfilling a deviation criterion;
subsequently, creating a signal indicating a guide rail buckling based on the deviation; and
sending the signal to trigger a guide rail maintenance alert,
wherein the first data is a distance travelled by the elevator component or a speed of the elevator component measured along a guide surface of the guide rail relative to the guide surface of the guide rail, and the second data is a distance travelled by the elevator cart or a speed of the elevator cart measured in a longitudinal direction of the hoistway of the elevator system relative to the hoistway of the elevator system.
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