A little help, CPR Alco fans

[sirenwerks]

I spied a pic of a CP Rail RS3 and the box the road has installed around the fan housing has me intrgued. I imagine it has something to do with the mighty winters they get up north, but can someone explain the specific why and how, and does anyone have a high shot of these rigs? This is what I'm talking about:





The SP&S, my hero, did something similar to its earlier phase units, but I am not sure if it was for similar reasons:

[Lenny53]

Yes, it is a winterization hatch used to recycle engine heat to keep the unit warm.

[Ed Kapuscinski]

It's got shutters in it to recycle some "heated" air that's passed over the radiators back into the car body of the locomotive for all sorts of uses in winter like keeping various things from freezing or getting below optimal operating temperatures.

Take a look at https://donstrack.smugmug.com/UtahRails/Locomotive-Details/Locomotive-Details/i-jfbTG77

[sirenwerks]

I get how winterization hatches work, and the SP&S hatch makes sense to me as the RS3 has one fan and the hatch covers that one fan, but has big louvers that can be opened to accomodate warmer/drier weather. But some of the environment the SP&S units operate in can be pretty freakin' cold somethimes and pretty damp, and then not so much; and Canada is more freakin' cold more often and it snows aplenty, from rumors I've heard. So the fact that the CPR hatch covers less than a fifth of the fan makes it seem less than optimal as a thermal circulation unit; or to keep out wetness/snow, if that's a thing the hatches are supposed to do. Why so far back? Did the SP&S units have pressurized engine compartments and the CPR units not (or do I have that backwards)?

I think this pic shows the set back of the hatch from the fan better:

[Ed Kapuscinski]

That SP&S fan situation could be a bunch of things. My guess is that it's not a winterization hatch but a rebuilt cooling fan setup.

The small amount of Alco overlap could be a bunch of things. My guess there is just that that's all that's needed. After all, I think there's less volume in an RS hood than a GP and especially an F or E.

[sirenwerks]

Maybe the designs have something to do with the nature of Alco exhaust? Afterall, you don't want to gunk up your engine with te thick emissions Alcos are known for. And yea, maybe the SP&S design serves another purpose. I'll have to reach out to the SP&S list.

[Ed Kapuscinski]

Maybe the designs have something to do with the nature of Alco exhaust? Afterall, you don't want to gunk up your engine with te thick emissions Alcos are known for. And yea, maybe the SP&S design serves another purpose. I'll have to reach out to the SP&S list.

There shouldn't be any exhaust in the mix (if everything's working right). All that comes out of that fan is hot air.

[cv_acr]

You know, I'm not sure why the ALCO/MLW winterization hatches don't cover the whole fan, but CP's FA-units similarly had covers that only hit part of the fan.

However.......

If you think about it, while EMD hatches cover an entire fan, EMD radiators have multiple fans not just one big one, so they don't cut off all the fans, just recirculate some warm air back into the hood. So actually you would not want to cover up the entire fan and completely block up the radiator.