A step back in time MTH catalogs spark question of the horsepower race

Idk of MK having a viable 7200 hp prime mover. EMD had a heck of a time with that H engine to generate 6000 hp. Reliably. 

If the H engine succeeded I believe that 6000 would have been the plateau in hp ratings and the focus would have shifted to better fuel economy and higher tractive effort. You also have to remember that "Tier 4 emissions" was being pushed on to the engines as well at that time. 

Who are the "we" in this land of make believe ?

prrhorseshoecurve posted:

Idk of MK having a viable 7200 hp prime mover. EMD had a heck of a time with that H engine to generate 6000 hp. Reliably. 

The issues with the EMD SD90MAC, were not necessarily related to the very big & heavy 4-stroke "H Engine". There were far more reliability issues with the electrical systems and the underframe.  Structure in the underframe had to be "compromised" in order to save weight, due to the MUCH heavier "H Engine", thus the units road pretty rough and some carbody &underframe cracking ensued. Remember that the SD90MAC units weighed something over 430,000 pounds.

If the H engine succeeded I believe that 6000 would have been the plateau in hp ratings and the focus would have shifted to better fuel economy and higher tractive effort.

The railroads quickly realized that 6000 HP units was NOT conducive to smooth operations. In fact, Conrail had an industrial engineering study done, in order to find out what the best overall unit horsepower would be be for THEIR railroad. As a result, the consulting firm recommended blocks of units with 5000 HP, thus Conrail purchase SD80MAC units. Ever since the entire railroad industry has "standardized" on units with 4300/4400 horsepower. 

You also have to remember that "Tier 4 emissions" was being pushed on to the engines as well at that time. 

Jim Berger posted:

Who are the "we" in this land of make believe ?

"We" were the same peoples that ran the "Land of Make Believe" and Mr. Roger along with the "Land of Hatchy Milachy" and Miss Judy.

Fascinating Hot Water! I didn't realize that there was issues with the frame. Curios you bring up a seldom talked about point in railroading... And that is load bering weight. Is there a maximum weight for locomotive development? Was it the whole package... that the prime mover along with the electrical components all sitting on six axle steerable trucks?

I read somewhere that 6,000 HP was just too much.  Suppose a train needs 12,000 HP to maintain a schedule.  Two 6K HP units would work but if one breaks down then the train isn't going anywhere.  If three 4.4K HP units are used then the train will have 8.8K HP to crawl home with if one breaks down.  The smaller HP units give the railroad more flexibility when matching HP to a train.

Having the highest HP possible per engine during steam engine days made sense since each engine required a separate crew.  The only way to get an engine over the road with one crew was to have big power - hence the Big Boy.

NH Joe

New Haven Joe posted:

I read somewhere that 6,000 HP was just too much.  Suppose a train needs 12,000 HP to maintain a schedule.  Two 6K HP units would work but if one breaks down then the train isn't going anywhere.  If three 4.4K HP units are used then the train will have 8.8K HP to crawl home with if one breaks down.  The smaller HP units give the railroad more flexibility when matching HP to a train.

Exactly correct!

Having the highest HP possible per engine during steam engine days made sense since each engine required a separate crew.  The only way to get an engine over the road with one crew was to have big power - hence the Big Boy.

NH Joe

prrhorseshoecurve posted:

Fascinating Hot Water! I didn't realize that there was issues with the frame. Curios you bring up a seldom talked about point in railroading... And that is load bering weight. Is there a maximum weight for locomotive development?

Generally, most railroads do NOT want to exceed 72,000 pounds per axle, thus the SD90MAC was 432,000 pounds total.

Was it the whole package... that the prime mover along with the electrical components all sitting on six axle steerable trucks?

I don't understand this question. Obviously the "whole package" was on the HT-CR "Radial" trucks.

Hot Water posted:

New Haven Joe posted:

I read somewhere that 6,000 HP was just too much.  Suppose a train needs 12,000 HP to maintain a schedule.  Two 6K HP units would work but if one breaks down then the train isn't going anywhere.  If three 4.4K HP units are used then the train will have 8.8K HP to crawl home with if one breaks down.  The smaller HP units give the railroad more flexibility when matching HP to a train.

Exactly correct!

Having the highest HP possible per engine during steam engine days made sense since each engine required a separate crew.  The only way to get an engine over the road with one crew was to have big power - hence the Big Boy.

NH Joe

 

I recall that the 6,600 horsepower Union Pacific DDA40X Centennials fell under the same concerns in an era when less than 3,000 horsepower was the norm. The DDA40X had two prime movers in it. But when they required maintenance, it was like two locomotives going out of service at once.

Jim R. posted:

I recall that the 6,600 horsepower Union Pacific DDA40X Centennials fell under the same concerns in an era when less than 3,000 horsepower was the norm. The DDA40X had two prime movers in it. But when they required maintenance, it was like two locomotives going out of service at once.

That was indeed a concern for all the other railroads at the time, i.e. 1964 when the first DD35 units came out. However, such was not much of a concern for the Union Pacific, maybe because their diesel locomotive maintenance was so good, which was still a carry-over from the days of their big, high horsepower steam locomotives. Corporate culture, you know. 

Sounds to me much like the horsepower wars of the 1960's muscle cars, where the ever increasing horsepower taxed the other components on the car not designed for that kind of power, they put high power engines into chasis and breaking and suspension systems designed for family cars to varying degrees, some of those cars were downright scary, the modern equivalent to them are balanced, they have a lot of power but also have well designed braking systems, suspensions, tires,chassis and so forth to match that power. I suspect knowing the way engineering often goes in big corporations, that they tried to minimize cost by reusing things from earlier, less powerful motors and found it was too unbalanced to work well (I claim no special knowledge of train engineering itself, so that is just speculation based on a lot of years of study of manufacturing and design processes).