tenders

[Anonymous]

i always wondered why the rear(water end) of the tender is always lower than the front (fuel) end. water is the problem, having to replinish more than fuel. it seems like if the tender was square, it would hold more water. the santa fe 4-8-4 tenders are the exception, or at least they look that way to me, that they may hold more water because the tender is tall on both ends. i think the water capacity is stored under the coal bunker too, but still if the rear end was as tall as the front, it would hold more water??

[samfp1943]

See page 66 of the June 2006, Trains "Ask Trains" column. The first item covered makes the case, and a little history on the Vanderbilt style tender vs the square style tender. Mostly, that it was a lighter construction and required less internal bracing, thus had more water capacity

Sam

[rrandb]

Plus weight was the limiting factor for water. You could hold more coal or oil ,volume wise, cause they weight less than water.

[TomDiehl]

Plus the coal bin floor had to be even with the cab floor. On hand fired locos, this was necessary for the fireman not to be stepping up and down while shoveling. On stoker equipped locos, the stoker screw was just below floor level and had to raise up the coal to get it in the firebox.

[Anonymous]

IN GENERAL:

1. being that water is heavy, you wanna lower its center of gravity.
2. water was placed behind the fuel because water will flow to you, the coal or wood wouldnt.
3. most water pumps i know of on steamers were gravity fed. the pump itself on the loco not tender. and always lower than the tender floor.

VANDY vs. RECTANGULAR:

1. is it the term bracing? or splash plates? which ever the factory calls it, there has never been in my travels enough of both in a rectanguler tender to lessen its capacity moreso than what a vandy can carry ( of equal size ). another reason is im sure vandys had them too! slosh is slosh no matter what the capacity or shape of tender.

2. we all know railroads through history have always pinched every penny. if vandies were cheaper ( less structural bracing = less money spent on steal not needed, less metal = less weight of tender for more load to pull etc etc ), then why didnt they dominate the rails?

3. heres one that will drop your highballs, a vandy, to keep its circumferance true can only get so great in diameter as to not interfere with clearances etc. Same holds true for a rectangular, they both can only be so wide. but the rectangular will gain in surface area because of the extra area inherant in its four corner design. EVEN WITH BRACING!
and say for a vandy and rectangular of equal length ( say for turntable purposes) the vandy would lose again in its ability to keep a true circumferance, meet width clearances while gaining in height as can a rectangular. Frankly, with all the facts, for two equal size tenders of diff type, youd have to stretch the vandy out untill it looked rectangular before it could hold the same gallons.

4. To think that a vandy could haul more coal or oil because it was a vandy simply isnt the case. Water was the primary need for a loco. true the fuels are lighter ( barely ), but now you need more space to store more. well that defeats the whole idea of making the tender lighter in weight because now your gaining it back using extra metal for a bigger bunker. And remember, fuel mileage always seemed to get better, but the water mileage didnt. This would be true for both tender types.

TRIVIA FACT:

1. A rectangular object is harder to roll over from sloshing water than a cylinderical object. ( side to side slosh ) There are many ways to explain this, heres the easiest....
a 2' cube half full of water, center of gravity is 1'. a 2' diameter 2' long cylinder half full of water, center of gravity 1'. both are equal right? well you know they arent. the cube has more surface area on the bottom than does the cylinder. thus more water below center of gravity thus less chance of rolling. ( some call this lowering the center of gravity ) and no, there were no slosh plates!


now we know the steel rail jockeys didnt go whippin round corners, they did reach high speeds on occasion though. and splash plates were invented for a reason! Vandy vs Rectangle is as old as Big Boy vs Allegheny. how ironic neither titan had a vandy!
makes ya wonder why tank cars are round huh! The study of tenders alone could take a life time. And true there has to be a reason for the vandy. comparability wasnt one of them. Steve, if ya wanna see some wild tenders take a look at the Pennsy Long Haulers. Or even a tank engine. sometimes called shop goats. They have fascinating tenders!

Sincerely,

Power at Speed

[tree68]

Tank cars are round because round requires no inside bracing. In fact, since tank cars are generally either empty or full, they don't need baffles.

That's why you don't see square submarines - in fact, deep submersibles have spheres for crew compartments - flaws notwithstanding, the more pressure you put on them, the stronger they get.

A square tank over a certain size needs some form of bracing or the sides will bow. Look at a cardboard milk carton... Modern tank cars don't even have a frame - the tubular form is strong enough to take care of that function as well as holding the product. Why one railroad adopted Vanderbilt tenders and another didn't - the discussion could go on for days.

Regarding fuel vs water, NYC used track pans to minimize the amount of water they needed to carry on some of their engines. They had enough fuel on board for the entire trip, but nowhere near enough water. More recently, it's been common to see an extra tender - for water - behind excursion locomotives.

[Modelcar]

...And what about the little yard engines of the Pennsy that had the tenders with the sloped back end....Wonder what was that reasoning. Perhaps the back side was cut down for visibility. It sure didn't add capacity to the "tank"..

[Anonymous]

Regarding Vandy vs. Rectangular, some later Vandy designs evolved into what's called the water bottom tender. The bottom retains the cylindrical shape, while the sides are flattened, and sometimes extended straight up to, or slighly curved into the top. Maybe someone can explain how these are braced.

UP tenders went through this evolution, those used on the early Mountains and 2-10-2's were traditional Vandys. The 4-12-2's had a full width, though still circular tank. The early Challengers and Northerns had flattened-side tanks, but still used 6 wheel trucks, while the later Challenger and Big Boy tanks were straight almost to the top, but needed the Centipede wheel arrangement to carry the load.

Regarding the coal portion being higher, UP and some other roads added coal boards to increase the capacity. Big Boys often had these. One reason may have been that many UP tenders were designed for either coal or oil. A seperate oil tank could be fitted inside the coal bunker space using an overhead crane. The oil plus extra steel would be quite a bit heavier than coal, so when coal was used coal boards were added. A number of Challengers and Northerns were converted back and forth to oil during coal strikes, other locos operated as oil burners when assigned to the west coast, but were converted to coal when they were re-assigned. 844 operated both ways at different times. 3985 may have as well, but probably with a 3700 series number.

[Anonymous]

Ahhh nice replies!

Firstly the smaller locos with slope backs had the sloped back just for visibility. it was a great idea! also locos of that size were usually close to water facilities and could be refueled rather easily.so trade capacity for vision. it must be remembered that tender size generally befitted loco size ( you wouldnt see a N&W Class A with a tender that belonged to an 0-4-0 ) which intern denotes job type. and we mustnt forget tenders evolved just as locos did. usually the loco first then the tender.

The tank car statement was a gag to see who was reading this stuff at 5 in the AM est. and what you say is true tank cars need not inside bracing because they are half the time, full. outside bracing yes. some dont have what we call a "conventional frame". really lends creedence to the strength of the hull when you think of todays high horsepower drawbar pulls. a vandy on the other hand gets empty and lighter every mile it rolls along, then slows down (slosh) then gets a green light again ( more sloshing) ya see what i mean?
so again is it bracing or splash plating? both really are the same its a two for one deal. the vandy just cant claim more gallons for equal size. they bracing required and installed by factory just didnt take that much surface area away from the water. the only true way to overcome this was as tree68 stated....
the NYC used track pans. not a bad idea. refuel plus do it on the go! true ya had to slow down to 45mph i think but thats better than 0! and it saves a boat load of fuel as we all know its easier to keep mass in motion than it is to stop it, start it again. this must not have been a real bad idea as more than NYC did this.
Now for this next part i would first like to site that i am a PM Fan which means I have more of a portfolio of PM and C&O stuff and east coast railroads in general. that said i dont have as many technical references for UP tenders although i have seen many times what you mention about an evolved vandy. in my opinion i believe it is a combination of the two types in an attemp to gain the benefits of both. Again, just my thought on it. Didnt the Yellowstone have this too? As for the centepede wheel arrangement, your right, thats an obvious one.... like we all know water is heavy. the U.S. Dept of Weight and Measure says water is 8 lbs to a gallon. which means right now your figuring how much wieght WAS on the rear truck of your favorite tender. Yeah, the figures are astounding! and as an added feature the centepede type spreads that massive load over a greater distance of railhead than say a commonwealth or buckeye truck.

Extra tenders are on excursions because there aint to many water towers left since diesels took over. And the ones that were left when diesels took ever werent used because, well, used for what? Again more money saved. MOW trains used retired and/or scrapped tenders for water bottles. it was a natural move to use one for these purposes.

As for the coal bunker end well, ya always try to cram in as much as ya can. we humans always want more bang for the buck so if ya can add a few boards to the side, ( which they did ) and you can still see around it ( which they could, barely) then you can work a lil bit longer before a refueling. sure beats buying a new tender. OR, if ya know ya have a heavier train today it will take a lil bit more fuel to ride over the same rails as oposed to yesterdays train of 1000 less tons. but you have the same tender. Ya pile more on top. I think most of us can say we have seen a few pictures where the coal was piled over the top of the cab.

Idealy folks like there is a car for each type of load there was a tender for each type of loco that had a specific job to do inherent to its design. we know the major roads and many of the smaller liked to experiment. Bigger Better Faster! and when some of them fine machines reached many years in age, how many times did their job description change? thus replacement tenders. ONE thing is certain.... ya never left home without it!

Sincerely,

Power at Speed

[Anonymous]

An interesting east/west comparison of the Centipede types is UP 844's tender compared to the NYC Niagra tenders. Both are similar designs with similar total weights, but the NYC version has more coal capacity but less water, most likely because of those track pans.

844's tender capacity is 23,500 gallons of water and 25 tons of coal(6550 gallons of oil). The Niagra's tender carries 18,000 gallons of water and 46 tons of coal. Doing the math at 8 pounds per gallon of water, it's virtually an even trade.

I'm guessing that the Niagra's stoker screw was among the longest ever used.[:)]

[markpierce]

One blessing of being an SP steam modeler is the variety of tenders the prototype used. Also, locomotives in the same class often had different tender styles as large-sized (and more modern) steam locomotives were retired before older, medium steamers, offering a wide-variety of appearances. (For example, many 2-8-0s received larger capacity tenders from retired 4-6-6-2s, 2-8-8-2s, and 4-8-8-2s.) My favorite tender types in order of preference are whaleback, semi-vanderbilt (larger diameter tanks being flat on top and bottom), rectangular, cylinder (used on some 0-6-0s), and vanderbilt. The longish four-axled vandys look awful "leggy" to me, while the beefy six-axled semi-vandys are "brutishly" appealing to me.

[tree68]

QUOTE: Originally posted by Modelcar

...And what about the little yard engines of the Pennsy that had the tenders with the sloped back end....Wonder what was that reasoning. Perhaps the back side was cut down for visibility. It sure didn't add capacity to the "tank"..

BINGO! And they were in the yard - the plug was right there...

Oops - Should have read all the posts first....[:D]

[Anonymous]

id have to cast my vote towards yee old rectangulars. they just seem to look natural behind any locomotive. and for such an odd name, the buckeyes were alot easier on the eyes than the commonwealths. i just wasnt a fan of the centipedes. Give me a Lima 22RE on a set of Buckeyes anyday!

Sincerely,

Power at Speed

[Anonymous]

The Illinois Central heavy freight power was 4-8-2's in the 2500 and 2600 series. The locomotives were basically the same but the 2600's had large six wheel truck tenders with a larger water capacity. The 2500's had smaller 4-wheel truck tenders which carried less water. To make up for this shortcoming the 2500's typically ran with a small auxiliary tender which carried only additional water.

[Anonymous]

wow!!, thanks everyone. lots of good info. for some reason, i thought the vandys held more water in a given area. i like the looks of the rectangular tender also. yall remember the B & O t3 mountains? some recieved "longhaul" vanderbuilt tenders in the 1950s for longer runs, but...they were longer than the original tenders, 65 ft.