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BAP BOXCAB QUESTION

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BAP BOXCAB QUESTION
Posted by BEAUSABRE on Wednesday, June 21, 2023 8:51 PM

I have just completed a long, long chase and am the proud owner of an HO Scale factory painted Butte, Annaconda & Pacific boxcab locomotive by Suydam. I have a question about its wheel arrangement - the prototype had four powered axles. But were they in separate trucks (B-B) or articulated frames (B+B). I can't tell looking at the picture

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Posted by BEAUSABRE on Wednesday, June 21, 2023 9:04 PM

BTW, this is one of two passenger locomotives - identifiable by having twin pantographs (freight units had one). They were geared for 45 mph operation and had a dynamotor to provide HEP for heat and lighting of their train. Usually that was a baggage car and two coaches running 4 times a day each way between Butte and the mine at Anaconda taking miners to and from their shift. Freight units were geared for 35 mph and operated in multiple hauling 60 car ore trains. 

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Posted by Erik_Mag on Wednesday, June 21, 2023 10:56 PM

I'm very confident that the the truck frames were articulated, since the Milwaukee GE boxcabs had articulated truck frames.

All of the BAP boxcab electrics had 2400V/600V dynamotors for control power, the passenger units tapped off of these to provide power for lighting using five 120V lights in series as comonly used for streetcars. Power for heating was 2400V carried by a wire supported above the passenger cars, with the fan motors connected between the "ground" end of the heating elements and ground.

Loaded running speed for the freight locomotives was 15MPH, this is the speed where the locomotive developed maximum continuous tractive effort. The rated maximum speed for the passenger locomotives was 55MPH, though hauling a short train would limit top speed to about 45MPH. Maximum continuous tracive effort was developed at 25MPH.

I remember Suydam had offered models of the BAP electrics - RMC had a notr about Suydam's offering in the August(?) 1967 issue.

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Posted by Pneudyne on Thursday, June 22, 2023 2:39 AM
These locomotives had articulated trucks, so were B+B.
 
They were fully described in GE Bulletin GEA 828 of 1928 February, “Electrification of the Butte, Anaconda & Pacific Railway”, reprinted in CERA Bulletin # 116, “Electrification by GE”, ISBN 0-915348-16-0.
 
 
Cheers,
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Posted by Overmod on Thursday, June 22, 2023 3:53 AM

You can tell the frames are articulated by looking at how the couplers are mounted.  They are on the truck-frame extensions on the outer ends.  Like the GG1 all the buff and draft and traction went entirely through the underframe, with the carbody just 'going along for the ride'.

To negotiate curves... the carbody would have a pin pivot on only one truck; the other would have bearing plates and a sliding arrangement lengthwise.

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Posted by Pneudyne on Thursday, June 22, 2023 4:09 AM
Couplers mounted on truck frame extensions is not necessarily an indication of articulated trucks.  There have been locomotives that had independent trucks, yet with truck-mounted couplers.  In that case the buff and drag forces were taken through the main frame between the truck pivots.  Examples were the two IC C-C experimental diesel-electrics of the mid/late 1930s.
 
 
Cheers,

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