What's the tank above the smokebox on some steamers?

[Hedron]

Quick question for many of you, but spare me an hour of google rabbit holes....TIA.

The chamber resting above the number board, before the smokestack.

[wazzou]

Feedwater heater.

Modified to add link.
https://www.steamlocomotive.com/appliances/feedwaterheater.php

[johnb]

Feedwater heater.

Modified to add link.
https://www.steamlocomotive.com/appliances/feedwaterheater.php

what the Grand Wazoo said

[mmagliaro]

And just to be more precise, that is an Elesco feedwater heater.  Some engines had a Worthington type, which looks kind of like a big "extra compressor" hung on the side of the boiler, and finally, there is a Coffin type, which looks like a big piece of overhanging "hood" that sticks out in front of the smokebox over the headlight.

[peteski]

Yes, the B&M Berkshire locos with a coffin type heater are my favorite. Unfortunately they were never made as N scale models.

[Hedron]

Thanks!

[Albert in N]

   Which type is this one on an old N scale Rivarossi mikado?

[johnb]

  Which type is this one on an old N scale Rivarossi mikado?

a pair of compound air pumps

[peteski]

Yes, those are air pumps on the smokebox. The feedwater heater is not visible in those photos.

[garethashenden]

And just to be more precise, that is an Elesco feedwater heater.  Some engines had a Worthington type, which looks kind of like a big "extra compressor" hung on the side of the boiler, and finally, there is a Coffin type, which looks like a big piece of overhanging "hood" that sticks out in front of the smokebox over the headlight.

The heater part of the Worthington type is a box in the top of the smokebox. If there's a rectangular thing in front of the smokestack, that's what you're seeing. But they did also come with giant feedwater pumps, which is what you references. All the other types of feedwater heaters had pumps too, but they weren't as massive.

[squirrelhunter]

I think there is some confusion here- the Worthington SA feedwater heater looks like a box protruding out of the top of the boiler and usually has a small, box like pump on pilot deck or one one side of the smoke box. The BLI PRR M1 4-8-2 has this setup.

The Worthington BL feedwater heater looks similar to an ovwrsized air pump and usually is where the air pumps are on most steamers. SP 2-10-2's are as easy to google example of a Worthington BL installation. The only version in N I'm aware of was part of the old GHQ kits to make the Kato 2-8-2 look like CB&Q or Southern prototypes.

The Elesco feedwater heater is usually hung from the top/front of the smokebox or sometimes on the pilot deck or kind of buried in the top of it. The Bachmann NYC 4-6-4 has an Elesco that is mostly buried in the smokebkx, the old Atlas 0-8-0 has one on the front.

Coffin feedwater heaters are either concealed inside the smoke box or look like a horseshoe shaped thing hung on the front of the smoke box. Frisco was a big user of Coffin feedwater heaters hidden in the smokebox, B&M's 2-8-4's are probably the best known example of front hung Coffin feedwater heaters.

[Chris333]

The heater with the tank in most likely a Essco, their pumps look very much like an air pump. The Worthington type is a box, and their pumps are very large.

Essco:
https://www.rr-fallenflags.org/el/loco/erie-s3204bba.jpg
Pump is on the side where the air pump was, air pump is now on the pilot.

Worthington pump on the side:
https://www.rr-fallenflags.org/el/loco/erie-s4013ggC.jpg

It just pre-heats the tender water before it is injected into the boiler.