A train operating company running services throughout the West Midlands in the UK approached PCMS Engineering regarding their rail oil analysis service after their class 172 fleet suffered from a series of turbocharger failures.
Their class 170 fleet also suffered the same symptoms of turbo failure/high carryover after changing from heavy duty diesel oil to traditional automotive engine oil.
Upon inspection, the turbo internals were saturated in a black oily residue with some solidified deposits. No evidence of any common mechanical fault within the fleet was found following investigations of the air intake and air compressor.
As automotive engine oil is common in both the 170 fleet and 172 fleet, PCMS engineers analysed and evaluated the current engine oil in use for chemical and physical characteristics (which is a common cause of increased carryover) by collecting oil samples and sending them to our dedicated oil laboratory for analysis.
After completing test types such as elemental analysis, soot, viscosity and total base number on the oil samples, no significant changes to the oil chemistry was identified.
The volatility test, which determines the evaporation loss of lighter volatiles in high-temperature service lubricants, was performed to determine the percentage evaporation loss (<13% as stated by MTU Category 3 specification) of the oil in use.
The following additional analysis techniques were also performed to determine the evaporation loss and turbo deposit composition:
- Gas chromatography: an analysis tool used to analyse compounds that can be vaporised without decomposition based on molecular polarity.
- Infrared analysis: used to identify compounds by measuring resonant frequencies when exposed to Infrared radiation.
The Infrared analysis confirmed that the deposits found on the turbo were comparable with the various components of the oil in use. The volatility test found that % of evaporation loss was greater than the specified value (13.3%).
There was also an indication of increased additive dropout and base oil additive separation when exposed to increased temperatures at the turbocharger.
To rectify the problem, the train operator’s oil supplier provided a higher quality engine oil which solved the issue and reduced downtime by eliminating the need for constant turbo repairs.
The train operator has since continued their partnership with PCMS Engineering by utilising our managed oil analysis service to keep their fleet of trains running to full capacity.
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For more information about our rail oil analysis service, contact us on 01709 876712 or email firstname.lastname@example.org