Demoted to B-unit, what does that mean?

Model Railroader General Discussion (Model Railroader)
1

I can read the following on the net about the D&RGW GP40 3066. ‘Demoted to B-unit’ What does that really mean?

I also wonder what the difference is between a GP40 and a GP40-2?

2

usually when a unit is involved in a major derailment and the cab is messed upretty bad but the prime mover is still running good the shop forces will remove the cab and all cab controls and enclose the cab area. the modern units are pretty much like their ancestors Boosters. these are also called cabless hood units.

the main differences between a gp40 and a gp 40-2 are mainly internal with upgraded electronics. i could be mistaken on that.

hope this helps

tom

3

“On January 1, 1972, EMD began production of a “Dash 2” line(designations are those of former models with “-2” added) of road locomotives. GMD of Canada built certain existing models into 1972. Dash 2 changes were mainly internal (a modularized electrical control cabinet was a major one). A few spotting features are consistent to the entire line: battery box covers on the frame in front of the cab do not have hinges or latches, but are bolted on; a sight glass to check engine water level appears in the upper half of the hood near the rear of the unit on the right side; and the sloping cab roof extends slightly beyond the rear of the cab.”

This is taken directly from “The Second Diesel Spotter’s Guide”. Tom, you are correct![:D]

Jeff

4

In the case of the Rio Grande units being demoted to B unit status, this meant that they could not lead. In the roster book Locomotives of the Rio Grande by the Colorado Railroad Museum it is noted that GP30s #3021-3028, GP35s #3029-3050, and GP40s #3051-3075 were reduced to B unit status in 1972.

From Rio Grande Railroad by Jim Griffin we learn that these B units did not get the newly required chemical toilets nor safety glass required by the Federal Railroad Administration for lead locomotives. Also stripped from the locomotives by Rio Grande were speed recorders, cab sunshades and all seats but the engineer’s chair. The engineer’s chair was left for hostler moves. [:)]

5

As others have alluded to already, a unit that has been demoted to B-unit only status may have “lost” its cab through damage, be unable to meet current saftey and operating standards to meet lead-unit specs, may be less reliable in operation and thus teamed with other units which could “carry” it should it fail out on the road, or in some cases be just too old to be considered for operation other than as a booster unit.

CNJ831

6

Here’s my version of a SOO SD40-2 that is now a B unit. It was originally rebuilt by another railroad, can’t recall the name right now. This one is somewhat different than other conversions as the dynamic brakes were moved to where the cab used to be. Mine was made from an Athearn model with parts from several others.


(clck on photo to enlarge)

Bob Boudreau

7

Thanks a lot guys for the excellent answers.

8

While the cabless conversion was used on some roads as stated above, SSW9389 has it exactly right. In the case of the Rio Grande, they never did rebuild any road-switchers without a cab. They simply stripped the equipment SSW9389 mentioned from the cab to save on maintenance costs on some older units.

On the Rio Grande, the first group of locos converted to B-unit status were the GP-35s. Later on, a few of the GP-30s and GP-40s were similarly converted. Thus these units would not be seen leading a loco lashup, but would rather be placed somewhere in the middle of the consist.
Mike Lehman
Urbana, IL

9

A nice custom made Union Pacific B-unit done by Jim Drennan of Northwestern Illinois Hobbies.

10

The Pennsylvania (and later PC) had a few GP9B units.

http://www.rr-fallenflags.org/prr/prr3816.jpg
http://www.rr-fallenflags.org/prr/prr3800s.jpg
http://www.rr-fallenflags.org/prr/prr3838ads.jpg
http://www.rr-fallenflags.org/pc/pc3801ags.jpg
http://www.rr-fallenflags.org/pc/pc3839ags.jpg
http://www.rr-fallenflags.org/pc/pc3834bgs.jpg

There was a kit available to convert Athearn’s GP9 (really a GP7!) into a B unit, but the manufacturer’s name escapes me right now.

11

tjs couldn’t say it better my self

nuet loke the pic of the UP.

12

Wow! Those two locos look creepy with no cabs.(good models, but creepy)

13

Also according to the January 1990 issue of Railmodel Journal the final GP-40-2 units have a free flow style blower duct similar to the SD-60.

14

this unit was originally rebuilt by the burlington Northern