Metra F-40-C units, what were the silver grills for?

[Railwaymodeler]

As we know, the F-40-C units Metra had were spottable from a long distance by the big silver grills on the sides.

I've been curious as to why they were built with such grills. I am guessing heat buildup from interior electronics or engines, but then, why don't the EMD FP-45s or F-40-PH units have these grills then?

Plus there is what appears to be a pair of metal doors on the side too. Were these access doors to something in particular?

These grills do remind me of how ALCO built some of their switchers and road switchers, with the big grill at the end of the long hoods.

[Busjack]

The only thing I can say is that when I was in elementary school, there would be field trips to the Monon yard, and they would parade us through the locomotives, and all the "Caution 600 [or was it 480] Volts" signs scared the you know what out of me.

[buslist]

As we know, the F-40-C units Metra had were spottable from a long distance by the big silver grills on the sides.

I've been curious as to why they were built with such grills. I am guessing heat buildup from interior electronics or engines, but then, why don't the EMD FP-45s or F-40-PH units have these grills then?

Plus there is what appears to be a pair of metal doors on the side too. Were these access doors to something in particular?

These grills do remind me of how ALCO built some of their switchers and road switchers, with the big grill at the end of the long hoods.

Simple answer is that they are not grills. They are stainless steel side panels. Were they chosen to reduce paint requirements or to try to match the look of the galary cars?

For that matter I wonder who speced the locomotives? Remember they way predate METRA and were purchased by 2 Mass Transit Districts, and carried Milwaukee Rd logos. Did the Milwaukee have a role in their purchase?

[Railwaymodeler]

They always looked like grills to me, but then, I never got quite close enough to tell.

In most pics, they look like grills to vent the engine room or something.

Seems even odder that they would just be side panels.

[pete6125]

They originally wanted the engines to be all stainless steel.But it would cost to much. So the stainless panels were the compromise.

[Railwaymodeler]

Do you know if they were to be all corrugated sides? Would be interesting if, years later, they'd find their ways onto the BNSF-Aurora line, seeing as the CB&Q had E-5 units with corrugated panels on the side.