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Class 90 particulates

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trebor79

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Bear with me, I've not gone mad but here's a very technical question...

Do class 90s make a lot of particulates? Either from brakes or traction motor brush wear or something else?

Reason is ask is twofold. One, whenever I see one pass, it's not uncommon to see it enveloped in a sort of greyish cloud, even at low speed so I don't think it's dust off the track.
Secondly, I'm currently sat in the first row of coach K on the GEML heading into London, right behind the loco. Something is making my nose run and chest tighten, and the curious Mk3 smell (a mix of mustiness, grease and the je ne sais quoit we all know) seems somewhat amplified and I overlaid with a smell that is redolent of the smell you get on the tube.
Makes me wonder if this isn't the best place to sit!
 
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AM9

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Whenever I see an electric loco I and surprised by the amount of cooling fan noise there is. Such a high volume of air being moved, (mostly independent of actual rail speed) must contain a degree of particulates gathered in the cooling path from faster running, braking and picked-up from other passing trains, (think of how many freight trains ply the GEML).
 

ac6000cw

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As far as I know, traction motor blowers normally pull relatively clean air from high up the bodyside, filter it to some degree, then blow it through the motors to vent at a low level near track level. I suspect that this might help stir up some of the dust and debris that is always on the track, in addition to the 'stirring' created by the turbulent airflow due to train movement.

Just look at pictures/video of trains in powdery snow to see how easily small particles are stirred up into a large cloud around the train.

Also in poor adhesion conditions there may be some sanding taking place during acceleration and braking, which also creates a dust cloud to some extent (sand is usually blown under the wheels using compressed air). For example, heavy freight locos working hard uphill with near continuous sanding can get enveloped in a 'sand cloud' - noticeable if it's backlit by the sun.
 
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TheEdge

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90s can be surprisingly light footed sometimes so it's not uncommon, even in summer, to see them dumping sand. This will often look like they are in a cloud of dust.
 
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