2-8-4 Berkshires vs. 4-8-4 Northerns

[BigBoyFan4006]

Was there any particular advantage of the 2-8-4's over the 4-8-4's, or vice versa as far as their design is concerned?

 

[haddock57]

The main advantage i seem to recall is the four-wheel leading truck was better at higher speed. And possibly the bigger drivers that could be fitted, but other than that i have no idea.

 

[jacksonbarno]

Also, a bigger boiler could probably be fitted, with the extra pilot truck wheel helping to absorb a bit more of the weight.

 

[KenRuof]

The 2-8-4 was built for fast freight, the 4-8-4 was for general use both freight and passenger. Also I remember reading an article about the Berk and it had a problem going faster that 65~70 as the drive wheels would bounce off the rails.

 

[nicky9499]

drive wheels...bounce off rails

 

[kws4000]

yes nicky, if they were not properly balanced then the rods would overpower the counterweights, or vice versa, and you would be "flying by the seat of your pants". More intense problems on the N&W K3 4-8-2 limited it to 35mph. Anything you hear about mallets being limited in speed was more likely due to boiler capacity than bad running gear.
As for benefits of 4-8-4 over 2-8-4, recall that the GN (or NP, I forget which) O8 2-8-2 exceeded severl Berk's tractive effert, the N&W J 4-8-4 as well, with UP FEF being on par with most. Boiler horsepower was generally higher for a Northern.
So there is no real difference btwn the two except for ride quality, so if you look at performance, Northerns win, but as for how a lok feels at the head of train, well, that's kind of subjective.

 

[nicky9499]

Thanks for another interesting and informative post. I learned something new today.

 

[SuperFudd]

The Berkshires were intentionally smaller to fit in the smaller tunnels and such in the older eastern US routes.

 

[kws4000]

The Berkshires were intentionally smaller to fit in the smaller tunnels and such in the older eastern US routes.

I wouldn't say that, given that they were THE largest power on the Pere Marquette, probably the same for the Nickel Plate, and Erie as well. Maybe on the B&A and the P&LE, perhaps they were cut down relatively speaking.

 

[SuperFudd]

To clarify. Berkshires were about as large as some east coast routes could handle. No Northerns there. Bershires were created for those routes. The 1976 Freedom Train was pulled by Northerns except on the east coast routes were a Berkshire was required.

 

[NickmantheBobert]

Although didn't several Major Eastern Railroads such as the C&O, NYC, and N&W used 4-8-4's quite commonly and I do think that the 4449 ran in the Southeast for the American Freedom Train. Edit I notice you said some eastern lines, so ignore this post.