Why are some older OHLE masts yellow?

[Transilien]

I have noticed this mainly on the West Coast Mainline in certain areas. Why is this the case?

 

[Southsider]

I have noticed this mainly on the West Coast Mainline in certain areas. Why is this the case?

Being painted. That’s the undercoat, silver top coat still to be applied.

 

[Scotty Dog]

Back in Railtrack days they set about repainting them. Many only received the mustard yellow colour undercoat, since then, like everything else lineside, they have been neglected.

 

[Dr_Paul]

I recently travelled from Euston to Birmingham and noticed that nearly all the OHLE masts were crudely daubed with a yellow or green paint (I'm colour-blind, so it might be some other colour). Any idea why?

 

[Nova1]

If it's green this would make sense to help it blend in with the landscape

 

[William3000]

If it's green this would make sense to help it blend in with the landscape

There are some green ones on the West Anglia Mainline near Harlow

 

[GRALISTAIR]

And of course fairly standard procedure (across most industries) to have the different coats- primer, undercoat/buildcoat and topcoat in different colours - makes it far easier. Yes, mustard yellow was/is usual undercoat.

 

[59CosG95]

There are some green ones on the West Anglia Mainline near Harlow

That's probably nature taking its course, rather than NR (or equivalent) interventions!

 

[matchmaker]

I thought the masts were hot dip galvanised?

 

[themiller]

Primer for zinc (galvanizing) is generally yellow. The patchiness found on masts is caused by the finish coat not having been applied and the weather stripping the primer - where the primer was thicker, it’s lasted longer.

 

[matchmaker]

Primer for zinc (galvanizing) is generally yellow. The patchiness found on masts is caused by the finish coat not having been applied and the weather stripping the primer - where the primer was thicker, it’s lasted longer.

So hot dip galvanising isn't used?

 

[edwin_m]

So hot dip galvanising isn't used?

Is it that new ones are treated in the factory, but hot dipping can't be done on site so they need some further treatment after a certain period? I remember seeing these on the southern WCML back in the 80s when they would have been about 20 years old - if they stuck to that cycle this would be their third repaint.

 

[Southsider]

I had a summer job painting the masts back in the mid 1970s. They would be about 15 years old at the time in the Glasgow area. The treatment regime was to remove rust with a wire brush then a yellow base coat, a green intermediate coat and a silver top coat. The bottom 18 inches or so was finished with bitumen based paint.

 

[GRALISTAIR]

So hot dip galvanising isn't used?

Yes at the manufacturing stage. Not on site.