GE trucks

[Speaking clock]

I'm not sure if this has been done before, but why do some GE u boats and -7's have EMD trucks while others have the truck seen on engines like the b39-8 (FB-2?), and occasionally a truck that looks like those used in early alco road switchers.

is there much of a difference by performance, or is it just from trade ins?

also, which was the most popular

[ndbprr]

It was done when trading in engines. There were some gp30s with Alco trucks from FA trade ins. It may not be as possible today due to a number of reasons such as controls and engine programming differences in the computers.

[CPM500]

The 'Alco B road truck' was characterized by many wear surfaces, i.e. pins/bushings, wear plates, etc. In other words, maintenance intensive. The frame was subject to twisting under high hp/axle ratings, which negatively influenced adhesion.

Accordingly, Alco came out with their 'Hi-Ad B truck around 1967 or 8, which addressed these issues. There was also a 'Hi-Ad' C truck, which was a replacement for the old 'Tri-Mount' truck, which the railroads saw as problematical.

Many GE B-B's used the Alco B truck salvaged from trade-ins, as you stated. The GE FB-2 truck was a derivation of the GE FB-3 truck, which dated from the days of the U28C. For a number of reasons, this truck became the standard for high hp GE B-B locos. These FB trucks featured a minimum of metal-on-metal wear surfaces.

The most popular truck: the EMD Blomberg B.

 

CPM500

 

 

 

 

 

[Overmod]

CPM500

These FB trucks featured a minimum of metal-on-metal wear surfaces.

But unless I'm badly mistaken, they accomplished this through the use of a great many elastomer pieces ... which did not age any more gracefully than things like rubber-block motor mounts, giubos (fascinating that BMW misspells these wholesale!), or driveline isolators in automobiles.  I believe we have had discussions about the problems this causes.