A system comprising an extendable conveyor having a fixed portion and movable portions, and a measurement system (130,140); the measurement system (130, 140) comprising a first sensor, a second sensor, and a control unit, the first sensor and the second sensor being mounted on the fixed portion; the movable portions comprising a first nested movable portion and a second nested movable portion; characterised in that the first sensor comprising a first transceiver, wherein the first sensor is configured to transmit a first light beam toward the first nested movable portion of the conveyor; the second sensor comprising a second transceiver, wherein the second sensor is configured to transmit a second light beam toward the second nested movable portion of the conveyor; and the control unit being communicably coupled with the first sensor and the second sensor, wherein the control unit is configured to: calculate a first distance between the first sensor and the first nested movable portion based on the first sensor detecting a first reflection of the first light beam from a reflector mounted in the first nested movable portion during a movement of the movable portions; calculate a second distance between the second sensor and the second nested movable portion based on the second sensor detecting a second reflection of the second light beam from a reflector mounted in the second nested movable portion during the movement of the movable portions; and calculate a difference value between the first distance and the second distance; compare the difference value with a predefined threshold value; halt the movement of the movable portions in an instance in which the difference value exceeds the predefined threshold value. the measurement system (130, 140) comprising a first sensor, a second sensor, and a control unit, the first sensor and the second sensor being mounted on the fixed portion; the movable portions comprising a first nested movable portion and a second nested movable portion; characterised in that the first sensor comprising a first transceiver, wherein the first sensor is configured to transmit a first light beam toward the first nested movable portion of the conveyor; the second sensor comprising a second transceiver, wherein the second sensor is configured to transmit a second light beam toward the second nested movable portion of the conveyor; and the control unit being communicably coupled with the first sensor and the second sensor, wherein the control unit is configured to: calculate a first distance between the first sensor and the first nested movable portion based on the first sensor detecting a first reflection of the first light beam from a reflector mounted in the first nested movable portion during a movement of the movable portions; calculate a second distance between the second sensor and the second nested movable portion based on the second sensor detecting a second reflection of the second light beam from a reflector mounted in the second nested movable portion during the movement of the movable portions; and calculate a difference value between the first distance and the second distance; compare the difference value with a predefined threshold value; halt the movement of the movable portions in an instance in which the difference value exceeds the predefined threshold value. calculate a first distance between the first sensor and the first nested movable portion based on the first sensor detecting a first reflection of the first light beam from a reflector mounted in the first nested movable portion during a movement of the movable portions; calculate a second distance between the second sensor and the second nested movable portion based on the second sensor detecting a second reflection of the second light beam from a reflector mounted in the second nested movable portion during the movement of the movable portions; and calculate a difference value between the first distance and the second distance; compare the difference value with a predefined threshold value; halt the movement of the movable portions in an instance in which the difference value exceeds the predefined threshold value.