Re: How much $ for a new locomotive ??

HKA,
You're right, however, superpower could be produced, also, the technology is the same, just bigger.
As for the single piece cast frames, I would go for a solid fabricated one any day. Castings have the annoying tendancy to crack right in the most expensive places.
With the CNC mills and other computerized stuff, flame cutters, plasma cutters, water cutters, tolerances could be maintained that would give a frame as rigid as cast, but without all of the finish work.
As for weight, how about some of those spent uranium shells that the government has so many of? They're heavier than lead. (Joke)
I would go for all roller bearing surfaces if it was my money. Why? Lower friction coefficient and lower maintenance costs.
I can personally attest to the durability and strength of roller bearings on freight cars. We don't have anywhere near the hotboxes that we used to with friction bearings. The boys on the NS Steam Crew used to swear by them. If you've ever used brass or babbett bearings for any length of time, during the initial break-in period, you do more swearing at them.
On the UP engines, only the axles are roller bearing, the rods are brass bearings. We swore at them a lot, too.
If I were going to build a steam locomotive today, I would employ the most modern metallurgy and technology available, bar none. After all, you are talking about a product where people are putting their lives on the line, but one to also make a profit for the owners.
Simple, Dependable and low maintenance would be the ultimate ticket.
Rick Steele