HUGE vs. TINY drive wheels - Why?

[Sedalia Dave]

 

 

 

 

[Trailrider #896]

In point of fact, steam locomotives like  the Burlington O-5b, a 4-8-4 Northern type were intended to develop maximum tractive effort at higher speeds. for use pulling heavyweight passenger trains and/or freights of considerable tonnage.  Smaller-drivered seamers were generally intended for starting and pulling tonnage "drag" freights, and developed more of their tractive effort for starting and maintaining heavy loads, but with limited speeds. The Burlington M-5a, 2-10-4 Texas type initially pulled heavy coal trains in Southern Illinois, until the "Q" decided they needed higher speeds (up to 55 mph) for timed freight operations. This was accomplished by reducing the diameter of the pistons, without changing the driver diameters. Diesel locomotives get best tractive effort for starting at low speeds, but, given the right gear ratios, can go at higher speeds. As mentioned in the video, it is much easier to add more diesel units for hauling heavier trains. All fun and fascinating!

[J-BAR #18287]

Good stuff!  Fun watching it on my big screen tv!!

[Subdeacon Joe]

I sort of knew about the difference in wheel size, but hadn't thought about crank position.

[Captain Bill Burt]

Interesting.  Kind of explains why my Camaro has 20 inch wheels.  I might be better off dropping down a bit for a lower top speed (I don't plan on going 180 mph anytime soon) for a bit more acceleration.  Those big tires just look good though...