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Re: Locomotive electrical systems
Author: Dr Zarkoff
Date: 08-01-2013 - 19:43
>I had the impression (riding behind a Trainmaster) that dice were rolled at every station stop to determine how far to open the throttle when leaving - they took off like a bat sometimes.
Sounds like an old wives's, I mean, and old railroader's tale.
>So how did the GP9's work?
Just like any other GP9.
>At that time they certainly had transition, but they also apparently were able to keep up more or less for acceleration.
This is because there were usually two of them per train, unless the train had three cars or less. Same for the 4450 and 4451.
>Then there were the F40s. Amtrak and original Caltrain versions had the constant-speed engine (for HEP) - so how were they controlled for traction power?
By throttle position and the load regulator. I'm not sure how compensation was made for the constant engine speed. All direct connected HEP generator-equipped locomotives are the same in this respect, F-40s (all models), F-59s, P-32s, P-40s, P-42s, and P32-ACDMs (including Canadian versions of each).
>Presumably by then transition was no longer required?
I sort of recall that the first F-40s may have had transition, but you can't take this to the bank. By the mid to late 1980s transition was obsolete, and any F-40s which may have been built with it were probably retrofitted.
>I have to admit that despite growing up in SF I never saw SDP45s in commute service. TMs and GP9s, yes (rode behind a few), and even once (late 1950s, I think) something steam, and later early Caltrain, but I guess other things went on while I was out of town in college and early jobs. Oh well.
The TMs had WH 6-pole traction motors, which could really put out. The down side was that they were really expensive to rewind compared to the 4-pole ones everything else had (not that rewinding a 4-pole traction motor to the tune of $30-50,000 in 1970 was "cheap").
>Thanks again for your time to teach a heavy equipment mechanic some new tricks!
Rule No. 27: don's use excessive force, get a bigger hammer.
Sounds like an old wives's, I mean, and old railroader's tale.
>So how did the GP9's work?
Just like any other GP9.
>At that time they certainly had transition, but they also apparently were able to keep up more or less for acceleration.
This is because there were usually two of them per train, unless the train had three cars or less. Same for the 4450 and 4451.
>Then there were the F40s. Amtrak and original Caltrain versions had the constant-speed engine (for HEP) - so how were they controlled for traction power?
By throttle position and the load regulator. I'm not sure how compensation was made for the constant engine speed. All direct connected HEP generator-equipped locomotives are the same in this respect, F-40s (all models), F-59s, P-32s, P-40s, P-42s, and P32-ACDMs (including Canadian versions of each).
>Presumably by then transition was no longer required?
I sort of recall that the first F-40s may have had transition, but you can't take this to the bank. By the mid to late 1980s transition was obsolete, and any F-40s which may have been built with it were probably retrofitted.
>I have to admit that despite growing up in SF I never saw SDP45s in commute service. TMs and GP9s, yes (rode behind a few), and even once (late 1950s, I think) something steam, and later early Caltrain, but I guess other things went on while I was out of town in college and early jobs. Oh well.
The TMs had WH 6-pole traction motors, which could really put out. The down side was that they were really expensive to rewind compared to the 4-pole ones everything else had (not that rewinding a 4-pole traction motor to the tune of $30-50,000 in 1970 was "cheap").
>Thanks again for your time to teach a heavy equipment mechanic some new tricks!
Rule No. 27: don's use excessive force, get a bigger hammer.
