This is a topic that's perplexed me for quite a while. Especially when it comes to the water cars used on Union Pacific and Norfolk Southern excursions.

Do the locomotives have the water transferred to their main tenders when stopped somehow? Is there a set of tubes that move the water from the canteen to the main tender?

I'm really curious as to how they work.

Original Post

@Andrew Boyd posted:

This is a topic that's perplexed me for quite a while. Especially when it comes to the water cars used on Union Pacific and Norfolk Southern excursions.

Do the locomotives have the water transferred to their main tenders when stopped somehow?

The "transfer" is continuous, as the auxiliary tender was level is continuously seeking the same level in the main tender. There are twin flexible hoses (about 4" diameter with quick disconnect Cam-loc fittings) at the lowest portion of each auxiliary tender and the rear of the main tender. No matter whether stopped or moving, the "transfer" is continuous.

Is there a set of tubes that move the water from the canteen to the main tender?

Twin flexible water hoses.

I'm really curious as to how they work.

Think gravity.

As Hot Water said, the two tanks are connected at the bottom by one or two large (4” diameter) hoses. When connected this way, they behave like one big tank.

Gravity does the “transfer”work.

In closed fluid systems, the fluid is dispersed equally throughout.  Think of our body's circulatory system. And auxiliary water cars coupled to locomotive tenders.

Anyone else have visions of what happens when the train with half full tenders hits a grade?  I realize its only 1% or so, but between the tender and the auxiliary tender that is some length for the water to be moving around.

Last edited by Bill N

@Bill N posted:

Anyone else have visions of what happens when the train with half full tenders hits a grade?

Well, if the descending grade is immediately after all the tenders have been completely filled, in the case of SP 4449 where the auxiliary tender is larger/higher than the main tender, the water overflows the main tender. Thus, the auxiliary tender transfer connecting valves are kept closed, until the water level in the main tender as been lower quite a bit. At that point, and the next convient stop, the interconnecting valves are opened, and then the water level equalizes.

I realize its only 1% or so, but between the tender and the auxiliary tender that is some length for the water to be moving around.

Not all that much, even on a 2% grade.

Hot Water,  you mentioned an interconnecting valve, are they manually operated valves or check valves that would allow flow to the main tender and prevent reverse flow to the auxilary tender?

@Pitts posted:

Hot Water,  you mentioned an interconnecting valve, are they manually operated valves or check valves that would allow flow to the main tender and prevent reverse flow to the auxilary tender?

All the valves on the rear or the tender, and the front & rear of the auxiliary tender/tenders, are manual. No "check valves" to get "gummed up". There are also 2 1/2 inch fire hose fittings on each side, at the rear of the main tender, as well as on each side at the front of the auxiliary tender/tenders, these also have manual shut-off valves. The fire hose fittings allow for taking on water, during over-night stops, from any fire hydrant (except for the city of Chicago, which uses a different thread configuration from the rest of the U.S.).

It is interesting that the original poster has not returned, after more than 2 days, to acknowledge whether his questions have been answered.

Slightly off topic but l wonder what railroads in the steam era  used auxiliary tenders, in addition to the two cited above ?  R.  Grande, C&S, D&SL,? C&O?

Slightly off topic but l wonder what railroads in the steam era  used auxiliary tenders, in addition to the two cited above ?

First, the "two cited above" are ONLY related to excursion service, i.e. NOT in the "steam era" (neither the SP nor the UP used auxiliary tenders).

R.  Grande, C&S, D&SL,? C&O?

The railroads most famous for using auxiliary water tenders, back in the steam era, were: N&W, IC, and B&O.

@Bill N posted:

Anyone else have visions of what happens when the train with half full tenders hits a grade?  I realize its only 1% or so, but between the tender and the auxiliary tender that is some length for the water to be moving around.

Absolutely nothing happens. The tanks have baffles in them to control the movement of the water within the tank.

You guys are really over-complicating this.

• Two tanks
• Hose at the bottom connects the tanks together
• With the interconnecting hoses, the water seeks its own level
• It acts like one big tank
• No check valves
• No pumps
• Just gravity

That's it.

In my defense Rich my technical knowledge tends to be towards 19th Century railroading practices.  At least one article I have read from that period discusses how tender derailments happened from water being thrown around in the tender.

@Bill N posted:

In my defense Rich my technical knowledge tends to be towards 19th Century railroading practices.  At least one article I have read from that period discusses how tender derailments happened from water being thrown around in the tender.

So,,,,,,,,,,that would tend to indicate that those tenders may not have had internal baffles?

Additional railroads that used auxiliary water cars were the DM&IR, CB&Q (out of Quincy, IL and Centralia, IL), CanadianPacific on Western Plains, SP in a few locations ( I have a calendar photo of a 4-8-0 pulling an aux water car - Bakersfield area (?) and 2-6-0's working in the Imperial Valley, Northern Pacific behind 2-8-2's, Pennsylvania RR in 1955 out of Renovo, PA, due to a power shortage forcing revival of steam usage in territory where water facilities had been removed, Great Northern, Missouri Pacific behind 2-8-2's and 2-8-0's. These are the railroads that come to mind - possibly a few more. Kansas City Southern behind 2-8-8-0's - maybe.

Additionally, D&RGW 2-8-2's, Durango-Farmington.  L131 2-8-8-2 helpers on Soldier Summit, UT. Rio Grande 3 cyl 4-8-2's running on the arid terrain west of Grand Jct, CO.  D&SL 2-6-6-0's and D&RGW L95/96 2-8-8-2's working up the Moffat Tunnel line west of Denver.  Uintah RR behind their 2-6-6-2 tank locomotives.

The last runs of steam on the Missabe Road were made with 2-10-2 #514 in Sept 1962 - employing one of their water cars.

Auxiliary water cars most frequently took the form of rebuilt steam locomotive tenders or tank cars.

Last edited by mark s
@Hot Water posted:

So,,,,,,,,,,that would tend to indicate that those tenders may not have had internal baffles?

That is my assumption.  I did a quick internet search to find out when internal baffles became common, but that came with nothing useful.

I like the Tennessee Valley auxiliary tender that they use behind the 630 & 4501. That’s my next acquisition😎

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Checked further - Kansas City Southern 2-8-8-0's did, indeed, use auxiliary water cars. They were built with tiny 10,500 gallon water capacity tenders.

IRM's 1630's original "auxiliary" tender.  Well, not quite...

While we did carry water in the milk cars tanks, it wasn't plumbed to to 1630's tender.  Instead the was a small gasoline pump in the car and we could connect a hose and run it to the water hatch while in the depot.

We never did need it when the mainline ended at Seeman Road.  1630 now has a more "appropriate" aux tender.

Rusty

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Last edited by Rusty Traque

It's been almost two weeks since the original poster ask his questions. I wonder if he is satisfied with the responses?

I'm pleased with the explanations. Very much in fact.