Electric, Diesel and Steam Locomotives

[Overmod]

IIRC the HTB truck came out of the cooperation of GM and ASEA in the early '70s (compare the trucks on the GM10B electric). I've always understood it as a zero-weight-transfer, high-adhesion design, not something optimized for ride or tracking quality. Peter (M636C) may know detailed information for you -- there was a thread on this subject a while back.

Might have been some patent issues that made it 'less preferable' than a Blomberg, or just not better enough to get railroads to stock two sets of pieces for four-axle power. My guess is that the move to six-axle power effectively killed the perceived need for fancy ZWT long-wheelbase B trucks for freight, and the world of two-axle trucks has gone in a very different direction after the '80s.

The truck must have worked well enough; UP had at least one of theirs running in 2000, and one of the SP units is still working (afaik) as TP&W 4056.

[Anonymous]

QUOTE: Originally posted by Sterling1

OK . . . I may have already answered this but I'm going to ask anyway:

http://www.railpictures.net/viewphoto.php?id=94122

The SP units are the only ones that seem to have this truck and the "elephant ears "
Did this "new" truck design help in the way of adhesion or ride or nothing?

UP's GP40X's also used the HTB truck.

The HTB was experimental and because of its poor riding characteristics, it was not used on later models.

[Sterling1]

Is there a reason for WP unit 707 for having this kind of headlight instead a vertical set?
http://www.railpictures.net/viewphoto.php?id=107255
Also is this extention common?
http://www.railpictures.net/viewphoto.php?id=107295

[Anonymous]

Just to clear up some confusion re: New Zealand Deisel Electrics.

EMD:
Class "DC" = EMD G22AR Rebuilt from EMD G12
Class "DBR" = EMD G18AR Rebuilt from EMD G8
Class "DFT" = EMD GT22MC Rebuilt from EMD GL22MC
Class "DQ" = EMD G18C

GE:
Class "DX" = GE U26C
Class "DH" = GE U10B

These are only the export models used in N.Z. I havent included locally made locos or locos from other companys just EMD and GE.

[jdkuehn]

SD20's are de-turbocharged SD24's rebuilt from ex-Southern and Union Pacific SD24's at Illinois Central's Paducah shops.  They were rated at 2,000 hp, and hence, I assume, the designation SD20.  During the rebuilding the dynamic brakes were removed and the cabs replaced (or added as the UP SD24's were cabless 'B' units I think), noses chopeed, and a new air intake and pressurized car bodies.  SD18's had 1,800 hp, so I guess IC figured SD20 made sense, even though EMD called their 2,000 hp SD's SD38's.  ATSF also rebuilt SD24's into SD26's retaining the turbo chargers and increasing the horsepower from 2,400 to 2,600 and adding a pressurzed car body and a larger fuel tank and moving the air tanks to the roof.  CNW also rebuilt SD24's of UP heritage by de-turbocharging them and blanking the dynamic brakes, but I think they called theirs SD18's as they were very similar to an as-built SD18 and also rated at 1,800 hp.

 Jason Kuehn