B'mn On30 tank cars: confused with the big differences in size. ????

[DennisBT]

Just ordered a single, (one in one box), tank car, p/n 27198.
Also ordered a pair, (two in one box), tank car, P/n 26521.
Huge difference in size. 
Why? 
Both billed as On30.
Just differences in prototype railroad build size? 
Nice cars;  like'em OK.  No problem there.
I don't understand size difference.
Thanks for tips,
Dennis

[dutchbuilder]

It is what it is, difference in size.
Have a look at the AHM tank cars, they are even bigger.

Ton

[Ken Clark]

  The size difference is likely due to the car lengths, a 24 ft car  (1 per box), versus the 18 foot cars  (2 per box).
Both are 0n30 models.

[dutchbuilder]

  The size difference is likely due to the car lengths, a 24 ft car  (1 per box), versus the 18 foot cars  (2 per box).
Both are 0n30 models.

And don't forget the track gauge.
A car for three foot gauge can be bigger than a car for thirty Inch or two foot.
The models Bachmann makes are not always from 30 inch gauge designs but can be from other gauges.
For instance the 18 footers are actually 30 Inch gauge
The 2-8-0 also.
But the Forney's are two foot gauge.
The ten wheelers are three footers.

Ton