Bombardier Shoreliner/Comet car body question

Everyone:

I have a question concerning the Metro-North Bombardier Shoreline/Comet aluminum car bodies:

Is that actual gray paint or a coating over the aluminum that some of the cars have?

They look really good with this feature and the contrast enhances the blue or red window stripes
that the cars have. Was this done to protect and/or extend the life of the aluminum?

I will thank all in advance for any input here...MACTRAXX

the end door cars during their overhaul had clearcoat applied , the brushed aluminium held to much dirt and grime.
the centerdoor cars have not this or overhaul done yet.

if you looked at them before the overhaul they were filthy

Dutch: Thanks - it IS a clear coat that those end door Shoreliner cars have.

I never realized that the brushed aluminum car bodies could retain dirt in time and become tough
to clean. Do you have any idea what the name or maker of the clearcoat that Metro North used?

The reason I ask is that Metro in Washington,DC is actually wrapping their aluminum car bodies of
their 3000 and 5000 series fleets and removing their brown window striping. Perhaps using clear
coat would make even better sense in the long run like it has for Metro North. MACTRAXX

not knowing brand sorry.

You folks probably already know this, but aluminum forms thin oxides that are whitish or greenish, that look ugly