Clarence,

I would disagree with you on this. Since "modern day" (for this list is 1959), we'll only talk about this and backwards. Tanks cars in petroleum service ranged from 6,000 to 12,000 gallons, with a few exceptions, with the most common sizes depending on the fleet (8K for SHPX, and 10 K for UTLX). The largest owners were the 3 leasing fleets, SHPX, UTLX, and GATX and those fleets were anything but uniform. The reason for that is pretty obvious if you think about it and that relates to the traffic. Bothe pre-WWII and post WWII, the basic traffic was from refineries to distributers and the distributers had different needs with respect to amount. Thus, the loadout at the refinery typically shows multiple different types of cars. There also wouldn't be long strings on tank cars out on the railroad with a couple of exceptions. One would be the local, serving the refinery. Both delivery of empty cars tod and pick of loaded cars from the refinery would be a string of different cars, as these cars would be split up at the local yard for their destinations. The other example might be a train like the PRR TRS symbols. Standing for "tank, reefer, stock", these trains were designed to expedite empties to get them off the railroad. Having all sorts of empties would mean a variety of cars. When we think about WWII, which is about the only time long strings of tank cars moved over major railroads for any distance, these were whatever car could be grabbed and so they were classic "dog's breakfast" of tank cars. 

Bottom line? For the purposes of this list, trains of tank cars should resemble trains of boxcars, with a stairstep effect (albeit perhaps more subtle) due to the variety of cars in service.

Regards,

Bruce Smith

Auburn, AL

From: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io> on behalf of Clarence Zink <clarence.zink@...>
Sent: Sunday, July 17, 2022 2:58 PM
To: main@RealSTMFC.groups.io <main@RealSTMFC.groups.io>
Subject: [EXT] Re: [RealSTMFC] UTLX Class X Tank Car Build

Jim -

I believe strings of "mostly the same" tank cars has been an industry practice for a long time.  I'm particularly fond of Sinclair tank cars and company history, and as vividly as 55 years of memory will allow, remember standing on the platform in Rock Springs, Wyoming in 1965 - 68, waiting for our summer camp group to arrive,  seeing long strings of identical tankers blasting by on the outer tracks.  The Sinclair refinery was +/- 150 miles to the east, at Sinclair, Wyo.

The really CRAZY part of that is that in trains going west, those long strings of tank cars passing the Rock Springs station in the afternoons were pulled by giant UP diesels with a hole in the middle!!  You could see right through them!!  It took 40 years for me to figure out those giant UP diesels, usually 3 in a row, were DD35's.  DD40's didn't exist in '65, '66, or '67, but I might have seen them in 1968.

Anyway, whenever I've seen long strings of tank cars, present day or past, they are "mostly the same", maybe with different road markings, but generally the same construction type.  If you're constantly shipping 100's of thousands of gallons of the same petroleum products to the same destination, why not use all of the same cars?  And stored cars seem to be "mostly the same" on the tracks where I've seen them stored.

I've enjoyed this discussion immensely, and got a lot of info out of it.

Thanks everyone!!

CRZ