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Why were E units not suitable for freight?

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Posted by Erik_Mag on Saturday, June 25, 2022 9:38 PM

Overmod

But (as I recall) the ATSF 1-Bs were done for improved guiding stability and lower oscillation at high speed

That's presumably related to why EMD continued to sell E's long after they started selling passenger F's - the A1A was probably better at high speed than the Blomberg two axle trucks.

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Posted by SD70Dude on Saturday, June 25, 2022 10:14 PM

What was the highest speed gearing anyone ordered F's with?  I know some E's had a maximum speed in the 115-120 mph range, and perhaps ran somewhat faster if the overspeed was disabled (not that crews would ever monkey with something like that).  

VIA and Amtrak both have pretty long track records running Blomberg B's in the 90-110 mph range under F40's and F59's, though from watching VIA's units bounce over switches at 70-80 mph I'm not sure how smoothly they ride.

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Posted by ATLANTIC CENTRAL on Saturday, June 25, 2022 10:35 PM

SD70Dude

What was the highest speed gearing anyone ordered F's with?  I know some E's had a maximum speed in the 115-120 mph range, and perhaps ran somewhat faster if the overspeed was disabled (not that crews would ever monkey with something like that).  

VIA and Amtrak both have pretty long track records running Blomberg B's in the 90-110 mph range under F40's and F59's, though from watching VIA's units bounce over switches at 70-80 mph I'm not sure how smoothly they ride.

 

The fastest gearing on F2's, F3's, F7's, FP7's and F9's was 56/21 for a top speed between 102 and 105 mph. The next gear ratio down was 57/20 rated for 95 mph.

The fastest E unit gearing was 52/25 for a rated speed of 117 mph. It is my understanding that many/most E units were geared 55/22 for max speed of 98 mph.

Sheldon

    

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Posted by bogie_engineer on Sunday, June 26, 2022 11:02 AM

ATLANTIC CENTRAL

 

SD70Dude

What was the highest speed gearing anyone ordered F's with?  I know some E's had a maximum speed in the 115-120 mph range, and perhaps ran somewhat faster if the overspeed was disabled (not that crews would ever monkey with something like that).  

VIA and Amtrak both have pretty long track records running Blomberg B's in the 90-110 mph range under F40's and F59's, though from watching VIA's units bounce over switches at 70-80 mph I'm not sure how smoothly they ride.

 

 

 

The fastest gearing on F2's, F3's, F7's, FP7's and F9's was 56/21 for a top speed between 102 and 105 mph. The next gear ratio down was 57/20 rated for 95 mph.

The fastest E unit gearing was 52/25 for a rated speed of 117 mph. It is my understanding that many/most E units were geared 55/22 for max speed of 98 mph.

Sheldon

 

These speeds for the F and E units are confirmed by Blomberg in a textbook on diesel locomotive trucks he co-authored in 1945 stating 95 and 117 mph for those trucks, respectively, of which I have a copy.

EMD's recent use of the B1 arrangement on the GT46PAC for India was driven by the need to save weight to meet the axle load requirement. Starting with the HTSC export frame developed for the GT46MAC, the truck engineer for that project was planning to use an A-1-A motor arrangement when I suggested a B1 arrangement should be considered, especially since it offered the possibility of elimination of the end transom to save additional weight. When studied for weight shift, it proved to be the best option for that given the traction motor orientation so that was path chosen. However, the truck engineer was afraid to remove the end transom for structural reasons (I would have done it if given the choice).

A few years later, the 4 motor arrangement for an SD70ACe-P4 was requested by sales to compete with the GE C4 and again, the B1 was considered the best performer.

However, none of us involved with these recent models were influenced or even knew of the 1B arrangement on the Santa Fe units. The GA12 was well known; EMD still has a flat car with loading grids on it that is equipped with the prototype for that truck. We didn't think of that as a 1B truck, rather just a "pony truck", as it was known, added on since it doesn't share a frame with the driven truck.

So thanks SD60MAC9500 for that historical information.

Dave

 

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Posted by BaltACD on Sunday, June 26, 2022 2:40 PM

ATLANTIC CENTRAL
 
SD70Dude

What was the highest speed gearing anyone ordered F's with?  I know some E's had a maximum speed in the 115-120 mph range, and perhaps ran somewhat faster if the overspeed was disabled (not that crews would ever monkey with something like that).  

VIA and Amtrak both have pretty long track records running Blomberg B's in the 90-110 mph range under F40's and F59's, though from watching VIA's units bounce over switches at 70-80 mph I'm not sure how smoothly they ride. 

The fastest gearing on F2's, F3's, F7's, FP7's and F9's was 56/21 for a top speed between 102 and 105 mph. The next gear ratio down was 57/20 rated for 95 mph.

The fastest E unit gearing was 52/25 for a rated speed of 117 mph. It is my understanding that many/most E units were geared 55/22 for max speed of 98 mph.

Sheldon

Still recall the cab ride I got on B&O #9 from Garrett to Chicago in 1959 or 1960 - Train left Garrett about 1 hour late - the headlight of #5 The Capitol Limited was seen coming in behind #9 running On Time as we departed.  Leaving Garrett, the engineer opened up the two E units on #9 and away we went across the flat lands of Northern Indiana - at several points in time I would stand behind the engineer and observe the speed recorder registering between 115 & 119 MPH.  #9 passed Pine Jct about 2 minutes ahead of schedule.  B&O had the high speed gearing on their E's, at least in that period of time.

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Posted by ATLANTIC CENTRAL on Sunday, June 26, 2022 3:00 PM

BaltACD

 

 
ATLANTIC CENTRAL
 
SD70Dude

What was the highest speed gearing anyone ordered F's with?  I know some E's had a maximum speed in the 115-120 mph range, and perhaps ran somewhat faster if the overspeed was disabled (not that crews would ever monkey with something like that).  

VIA and Amtrak both have pretty long track records running Blomberg B's in the 90-110 mph range under F40's and F59's, though from watching VIA's units bounce over switches at 70-80 mph I'm not sure how smoothly they ride. 

The fastest gearing on F2's, F3's, F7's, FP7's and F9's was 56/21 for a top speed between 102 and 105 mph. The next gear ratio down was 57/20 rated for 95 mph.

The fastest E unit gearing was 52/25 for a rated speed of 117 mph. It is my understanding that many/most E units were geared 55/22 for max speed of 98 mph.

Sheldon

 

Still recall the cab ride I got on B&O #9 from Garrett to Chicago in 1959 or 1960 - Train left Garrett about 1 hour late - the headlight of #5 The Capitol Limited was seen coming in behind #9 running On Time as we departed.  Leaving Garrett, the engineer opened up the two E units on #9 and away we went across the flat lands of Northern Indiana - at several points in time I would stand behind the engineer and observe the speed recorder registering between 115 & 119 MPH.  #9 passed Pine Jct about 2 minutes ahead of schedule.  B&O had the high speed gearing on their E's, at least in that period of time.

 

Yes, I believe they all had the high speed gearing on the B&O, and that is why trains crossing the mountains on the old mainline often had 3 or 4 E units, geared for speed, not for power, on a railroad were most passenger equipment was rebuit heavyweights.

Sheldon

    

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