Southern Railway Aplhanumerics

[Evergreen24]

Whenever I see a Southern Railway locomotive, I notice that there is a letter after the number. What does it mean? And how does it benefit the railroad?

 

For Example:

Southern Railway EMD GP18 #189F

http://southern.railfan.net/images/archive/southern/gp18/sou189.html

 

Any help would be greatly appreciated.

- Fernando Uribe

[tdmidget]

 

A better question is where did you see a Southern Railway locomotive of any kind?
The image is from 1974. The merger with N&W was about 30 yrs ago.

The loco pictured is sub lettered NS which was the old Norfolk Southern, a short line in Virginia . I don't know for sure but as Southern still had passenger service at this time, it may mean "freight", as in no steam generator.

[Evergreen24]

Well I actually didn't mean of the sublettering, I meant more of the letter after the locomotive's number.

The link below is what I'm asking what the small "X" meant on 3508 and the "R" on 7013.

 

GE B30-7A1 #3508X &GP50 #7013R

http://southern.railfan.net/images/archive/southern/b30/sou3508.html

[1019x]

It was called a check digit. Each unit was assigned an Alfa character based on a formula where each individual number was assigned a value, which when combined created a value that corresponded with an assigned letter. The idea was to improve accuracy of reporting. For example someone with poor handwriting might write down 3013 and someone else might read it as 3018. If you tried to enter 3018 with the check digit corresponding to 3013 into the data system you would get an error message. This started in the early 70s. After the NS merger use of the check digit was dropped.

Charlie

[Paul_D_North_Jr]

Charlie/ 1019X has it right.  There were a couple of letters or columns and at least 1 photo essay about this in Trains back in the 1970s - eventually someone explained the code in detail. 

Lament for a lost locomotive
Trains, August 1980 page 20
Southern Railway 3301
( DIESEL, "DOODY, BERNARD J.", EMD, FRONTISPIECE, SD40-2, SR, ENGINE, LOCOMOTIVE, TRN )

How accurate Southern?
Trains, March 1969 page 16
Southern's computer car locating system
( COMPUTER, "EDMONSON, HAROLD A.", SR, TRN )

- Paul North.

EDIT / P.S. - See also the explanation of ''Southern Railway Locomotive Check Codes'' at -

http://southern.railfan.net/check.htm  - PDN.

[Paul_D_North_Jr]

Following-up on my previous post -

The 'check letter' code was also explained in the same August 1980 issue of Trains, in the first entry of the "Second Section" column on pages 58 - 59.  The algorithim/ formula appears to be the same, just explained a little differently.  If I have time later this week I'll retype it here.

- Paul North.