Where low adhesion is permanent

Travelling between St Pancras and Derby earlier today, I noticed the up slow line between Bedford and London in places has warning signs of low adhesion (If the down slow also has problems I didn't notice), something that was in place 3 years ago as well when I last used the line.

Does anyone know why low adhesion might be an apparent permanent issue? I know temporary causes would include ice, water, leaves, etc., but I suspect none of those apply here. My initial thought was poor rail quality, which might explain new looking track in places, but I'm not completely sure.

Also are there any other examples of permanent adhesion problems on the network?

There are hundreds of places that are classed as low adhesion all year round, the reasons are many and varied, a cynic might say it is a way to transfer blame for an overshoot/slide through onto the driver because they should have allowed for the known poor rail adhesion, not that I would of course!

One permanent low adhesion area on my route is between Stetchford and Birmingham International due to pollution from jet fuel. There's also knows areas like Kronospan in Chirk with the dust from all the woodchip. I don't know the area you're on about but is there a lot of industry or lots of farm crossings about? Possibly an airport? What's the gradient like? These always going to be a multitude of answers for this question but in my experience these are the most common outside of leaf fall season.

Micheldever can be slipped through quite readily, especially if there's been a light shower and the grain plant has been working hard.

sw1ller said:

One permanent low adhesion area on my route is between Stetchford and Birmingham International due to pollution from jet fuel

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Is this jet fuel pollution dropping from the sky or is it something else, e.g. seepage from fuel storage tanks?

damo44 said:

Is this jet fuel pollution dropping from the sky or is it something else, e.g. seepage from fuel storage tanks?

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I'd imagine it is largely from evaporation and some from exhaust.

The line between Severn Tunnel Junction and Newport past the west end of Llanwern steelworks used to be a low adhesion area prior to the closure of the blast furnaces in 2001.