![A Southern Pacific 2-8-2 Mikado steam locomotive with a Vanderbilt oil tender is seen in a 1916 builder’s photo](https://www.trains.com/wp-content/uploads/2022/06/MRR-Ask-MR-0922-Southern-Pacific-2-8-2-Vanderbilt-tender.jpg)
Q: Why do Vanderbilt tenders have round tanks? It seems to me that with the same principal dimensions, a Vanderbilt tender would contain less water than a rectangular tank. – Chuck Moore
A: The answer is hydrodynamics. Vanderbilt tenders have round tanks because they have to hold a lot of water. The radial bands of a cylindrical tank are better able to withstand the strain of carrying that much water than the right-angle welds at the edges of a rectangular tender.
Improved visibility is another reason Vanderbilt tenders have round tanks. Since Vanderbilt tenders are narrower at the back, that makes it easier for the cab crew to see their train when backing up.
Reader Tip: Holders for cell phone throttles
Many operators are downloading apps that let them control a Digital Command Control-equipped layout with a smartphone. These apps are great, but despite our best efforts, we often end up setting the phone on the layout when we need a hand free to uncouple cars or sort waybills. This can damage scenery or structures on our layouts. The solution is adjustable automotive cell phone holders. Bolt the base plate to the layout fascia, and the phone can be easily clamped in. This holds the phone, protects the scenery, and most importantly still allows you to use the phone as a throttle. – Jonathan Miner
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