Hey Guys
I havn’t been posting for a while (I was diagnost with Multi myaloma at the end of 2013) but I follow the forum every morning. I see that NKP’s 2-8-4 is back in steam and was wondering how it compares to the heavy mountain 4-8-2. The reversed wheel pattern intrigued me.
Have a good day.
Lee
I’d think having the 4 wheel trailing truck would support a heavier and larger firebox. But that is just speculation based on some of the reasons stated for locomotives to gain trailing trucks in the first place.
All I know is that I had a great day Satruday riding behind 765 over some trackage that hasn’t seen a passenger train in my lifetime, let alone one with a steam locomotive. ANd some other of the most beautiful scenery in the state, which does have regular scenic excusrions, and then some other that I was only over before because of a rare mileage fan trip I was on a couple of years ago. Heck of a ride, and it seemed like 765 had no problems with the 19 passenger cars, tool car, and aux canteen. Though I have since seen some video taken trackside where she definitely had instance of wheel slip climbing the grade on the old Lehigh Valley line.
–Randy
A few things regarding a Bershire Type versus a Heavy Mountain Type.
Although the Bershire type was used in Passenger Service on Excursions, its primary service in normal service was freight, and in the case of the Van Swearagin Berkshires High Speed freight. The Original Mountains were orginally designed for hauling heavy passenger trains in the mountains.
The Van Swearagin Berkshires had 69" Drivers (while some had only 63" Drivers for added tractive effort) versus the Heavy Mountains 72" Drivers which in theory gave them added speed along with a 4 wheel leading truck which was more stable at speed.
The main difference was the size of the firebox, the four wheel trailing truck allowed for a larger size firebox which allowed for more steam. In the early 1900’s engines could go at a high rate of speed but soon ran out of steam to keep that speed up, the larger firebox allowed by the 4 wheel trailing truck meant the engine could keep up the speed allowed by higher drivers for a longer period of time.
Now, that is all thoretical, some railroads specifically the NYC and PRR used Heavy Mountain types primarily in high speed freight service and only had Berkshires in specialized (namely the P&LE and B&A Berks with the smaller drivers for heavy mountain hauling). Also, the NKP had outfitted some of their Berks for hauling heavy troop trains during WWII.
Rick J
Lima designed the original 2-8-4 as a ‘super-Mikado,’ with a big firebox over that 4-wheel trailing truck to generate more horsepower at higher speed than a standard 2-8-2.
The 4-8-2 was meant to be a ‘super-Pacific,’ with more tractive effort for mountain climbing, but not necessarily higher horsepower, than a 4-6-2.
Two different philosophies, two different kinds of service. Truly an ‘apple vs orange’ comparison.
Chuck (Modeling Central Japan in September, 1964 - sans 4-wheel engine trucks)
some NKP berks were outfitted for passenger, perhaps for troop trains but in some backup passenger runs. 765 WAS one such engine. The NKP berks were a compressed down C&O 2-10-4, if you look at the 2 the designs look obviously similar. Basically the 2-8-4 was an enlarged 2-8-2.
And the C&O 2-10-4’s were enlarged Erie 2-8-4’s.
Rick J
Interestingly, there WAS a super-Mikado. It had a grate area 10% larger than an NKP Berk.
Great Northern O-8.
Ed
Thanks to everyone for all the information. I enjoy the insite. When looking at an HO model, it’s not obvious, the many considerations that have to go into designing the full 1=1 machine. Considering the time frame, when the big articulated locos were built the expertice needed was not all that different than building the space shuttle in the computer age.
Thanks again.
Lee
Lee, hope everything is going well for you, God bless,
Ralph
Thanks Ralph
Apart from being weak, I think we have things on hold for now. I had a stem cell transplant and that is supposed to be very good at keeping the multi myaloma at bay.
Have a good one
Lee
Charlie 9 Did you get my return EMail?
Lee