Well, the original string got carried in another direction, so here's my two cents on the first item.
Controllers frequently get changed out with a UTEX part of the same or similar part number.
There are many roller switches, cams, etc... to wear out so it is not infrequent that we change them.
It isn't hard for most diesel electricians to replace one controller with another containing more or fewer options than the former part and still get the desired result.
I have done straight forward one-for-one changeouts as well as converting from single handle to two handle ("AAR type"). One of the more unique cases was a GP-20 rebuilt by ATSF in 1980. These units incorporated TWO "power" selections instead of one. Position One being for "Road" Position Two being "Switch" (AKA "Accelerated Start"). Naturally the UTEX controller was of the more generic Power-off-Dynamic configuration, so I had to do a little "reverse engineering" by installing a standard EMD slide-type "Accelerated Start Switch" in the original location of said switch on the control stand.
You can tell the vintage of the controller on your unit by reading the first two digits of the serial number. That gives you the last two digits of the year it was manufactured. It may very well be older OR newer than the unit it is applied to!
There are three basic types of "modern" EMD controllers that I am aware of. First was the one handle type with a ratcheting selector to switch from power to dynamic. I have seen this type applied as far back as the GP-9. The second type has a single throttle/dynamic handle, but the selector simply slides forward and back to select power or dynamic. The third is the familar "AAR type" two handle controller, with one handle for Power and one for Dynamic Brake.
Likely, the controller in that particular GP38-2 was from an older unit which either had manual transition or was likely to lead other units equipped with manual transition.
Loco parts never seem to really die, they just get rebuilt and reused over and over. I have seen EMD D77 and D78 traction motors in SD40-2s with frame casting dates from the 1940's (of course the insides have been replaced a few times, but still!)
The big problem with these old controllers is that the selector mechanisim can wear out causing the unit to remain in power mode when dynamic braking is selected. If parts and time allow, I prefer to upgrade from one handle to two handle controller when replacing this part.
Controllers frequently get changed out with a UTEX part of the same or similar part number.
There are many roller switches, cams, etc... to wear out so it is not infrequent that we change them.
It isn't hard for most diesel electricians to replace one controller with another containing more or fewer options than the former part and still get the desired result.
I have done straight forward one-for-one changeouts as well as converting from single handle to two handle ("AAR type"). One of the more unique cases was a GP-20 rebuilt by ATSF in 1980. These units incorporated TWO "power" selections instead of one. Position One being for "Road" Position Two being "Switch" (AKA "Accelerated Start"). Naturally the UTEX controller was of the more generic Power-off-Dynamic configuration, so I had to do a little "reverse engineering" by installing a standard EMD slide-type "Accelerated Start Switch" in the original location of said switch on the control stand.
You can tell the vintage of the controller on your unit by reading the first two digits of the serial number. That gives you the last two digits of the year it was manufactured. It may very well be older OR newer than the unit it is applied to!
There are three basic types of "modern" EMD controllers that I am aware of. First was the one handle type with a ratcheting selector to switch from power to dynamic. I have seen this type applied as far back as the GP-9. The second type has a single throttle/dynamic handle, but the selector simply slides forward and back to select power or dynamic. The third is the familar "AAR type" two handle controller, with one handle for Power and one for Dynamic Brake.
Likely, the controller in that particular GP38-2 was from an older unit which either had manual transition or was likely to lead other units equipped with manual transition.
Loco parts never seem to really die, they just get rebuilt and reused over and over. I have seen EMD D77 and D78 traction motors in SD40-2s with frame casting dates from the 1940's (of course the insides have been replaced a few times, but still!)
The big problem with these old controllers is that the selector mechanisim can wear out causing the unit to remain in power mode when dynamic braking is selected. If parts and time allow, I prefer to upgrade from one handle to two handle controller when replacing this part.
. Good info ,thanks.