CM Survey Prevents Bearing Failure on London Underground Escalator, Resulting in £8,000 Cost Avoidance

PCMS Engineering carried out a condition monitoring survey on two escalator drive gear trains (E9 and E11) at Tottenham Court Road tube station.

The Challenge

The purpose of the survey was to confirm if any adverse or unwanted vibration was being experienced on newly installed gearboxes, following reports of unexpected vibration and deflection during operation.

Due to operational issues on the E11 escalator drive, data was only collected on the E9 drive.

The Solution

Standard vibration and stresswave data were acquired using a CSI 2140 Four-Channel Machinery Health Analyser with a 100mV/g accelerometer fitted with a dual-rail magnet mount

The Results

Analysis of the vibration and stress wave data revealed an inner race bearing fault in the spectrum and waveform on the RH worm box input shaft thrust bearing (6312) – see figure 1.

While stresswave levels were low, due to the criticality of the asset, the bearings were recommended for an overhaul to prevent in-service failure. Further routine monitoring was recommended.

For more information on our rail thermal imaging surveys, contact us on 01709 876712 or email info@pcmseng.co.uk

Figure 1: RH input shaft worm box stress wave spectrum