UP 9000 Tender Question.

May look small, but that is one huge tender.  I could look it up, but I bet it holds more than an SP 160C, and that tender was adequate for cab forwards.

A division point was only about 100 miles or so, back in the mid to late 1920s, when the 9000 class locomotives where developed. Plus, the turntables were not that big then either. Whater could obviously be taken enroute, and the UP also had main line coaling facilities strategically located.   

Lots of steam engines had smaller tenders than what they should have had. The size reduction was due to turntables where not enlarged for bigger engines over time.

There are so many factors on how much fuel a steam engine would use. Water was mostly the limiting factor.

What really surprised me reading up on this, was usually a certain water level was required to keep traction effort up and the tender weighed down.

On the average I believe most steam engines traveled about 90 miles before refueling.

The first batch of 4-12-2s held 15,000 gallons of water and 21 tons of coal.  The later batches had 18,000 gals and 22 topns of coal.

 

ChipR

The 9000's were built before the development of the "centipede" 4-10-0 tenders seen on the NYC, DM&IR, UP, L&NE, B&M, etc. Those were developed during WW II. If you would care to see a rather comical tender, check the Central of Georgia's 4-8-4! Again, turntable length was a limiting factor.

Huh?? I've never heard this before.

Water and fuel levels make a difference in tractive effort on tank engines, but not tender-equipped locomotives.

 

 

That depends on way too many variables, i.e. size of locomotive, size/type of train, track profile, and the time era you are discussing (19th or 20th centuries).

I'm pretty well acquainted with one particular tank engine, and water/fuel levels don't seem to make a noticeable difference.

 

I'm sure weight on drivers plays some role, but in all the formulae for tractive effort I've ever seen, there is no provision for weight on drivers/coefficient of friction.

In theory though, it would have to make some difference, depending on the capacity of the tank.  The South African Garratt locomotives, though they admittedly had larger fuel/water capacities, lost tractive effort as they used coal and water.

Only possibly when starting a train. After the train is moving, it is all about horse power!

Was the tender size about the same as the yellow one used behind the main tender on 844 and 3985?

Similar, but not exactly the same. The current auxiliary water tenders, were from the Gas Turbines, and prior to that they were the tenders from the FEF-1 4-8-4 locomotives (sometimes called the "little 800s"). In fact, if one looks closely at photos of those auxiliary water tenders, you will see the ORIGINAL 800 class road number shown on them.