These locomotives were renumbered, between 1983 and 1991, by adding 100 to their original road no. The renumbering was done when their as-built A1A-A1A trucks were replaced with B-B Flexicoil trucks from retired GP9s and they received a 2,000 gallon fuel tank.
Trucks: B-B Flexicoil
Engine: 12-567C, 1,200 hp
Gear ratio: 62:15
Maximum speed: 65 mph
Operating weight (lbs.): 247,000
Tractive effort: 44,900
Length: 54′ – 9″
| Road nos. | Class | Original road no. | Renumber date | Retired date | Subsequent road no. | Disposition / notes |
| 1101 | GR-12m | 1001 | Jul 8 83 | Aug 8 97 | ||
| 1105 | GR-12m | 1005 | May 14 85 | Aug 8 97 | To Taylor Group (Greenville, MS) 1998, to CASCO No. 1105 | |
| 1106 | GR-12m | 1006 | 1987 | Dec 18 97 | To Cuban National Railway No. 51201 | |
| 1113 | GR-12m | 1013 | Dec 9 85 | Feb 6 98 | To Cuban National Railway No. 51202 Dec 99 | |
| 1115 | GR-12m | 1015 | 1987 | Dec 18 97 | To Cuban National Railway No. 51203 Dec 99 | |
| 1116 | GR-12m | 1016 | 1988 | Apr 24 98 | To Taylor Group (Greenville, MS) 1998; To Southern Railway of British Columbia No. 1201, to JLCX 2014 | |
| 1117 | GR-12m | 1017 | May 4 83 | May 16 96 | ||
| 1118 | GR-12m | 1018 | Oct 14 83 | May 26 96 | To Canadian Railserve: To Central Western No. 1118, to Alberta Prairie No. 1118 | |
| 1120 | GR-12m | 1020 | Nov 30 83 | Jan 26 98 | To Cuban National Railway No. 51204 Dec 99 | |
| 1121 | GR-12m | 1021 | Oct 31 85 | Mar 30 96 | ||
| 1123 | GR-12m | 1023 | Jun 19 83 | Feb 6 98 | To Cuban National Railway No. 51205 Dec 99 | |
| 1124 | GR-12m | 1024 | Jun 29 83 | Dec 18 97 | To Cuban National Railway No. 51206 Dec 99 | |
| 1127 | GR-12m | 1027 | 1987 | Apr 30 98 | To Taylor Group (Greenville, MS) 1998 | |
| 1129 | GR-12s | 1029 | 1988 | Dec 29 97 | ||
| 1130 | GR-12s | 1030 | 1987 | Jan 26 98 | To Cuban National Railway No. 51207 Dec 99 | |
| 1133 | GR-12s | 1033 | Nov 30 83 | Feb 5 98 | To Cuban National Railway No. 51208 Dec 99 | |
| 1134 | GR-12t | 1034 | 1987 | Apr 28 98 | To Cuban National Railway No. 51209 Dec 99 | |
| 1139 | GR-12t | 1039 | 1987 | Feb 25 98 | To Cuban National Railway No. 51210 Dec 99 | |
| 1140 | GR-12t | 1040 | Mar 24 87 | Jan 26 98 | To Cuban National Railway No. 51211 Dec 99 | |
| 1141 | GR-12t | 1041 | Oct 25 83 | Aug 8 97 | ||
| 1143 | GR-12t | 1043 | Oct 25 83 | Apr 21 98 | To Dardanelle & Russellville No. 20 1999 | |
| 1144 | GR-12t | 1044 | 1987 | Mar 31 98 | To Taylor Group (Greenville, MS) 1998 | |
| 1147 | GR-12t | 1047 | 1987 | Dec 18 97 | To Cuban National Railway No. 51212 Dec 99 | |
| 1148 | GR-12t | 1048 | 1987 | May 10 96 | ||
| 1149 | GR-12t | 1049 | Dec 31 83 | Mar 31 98 | To Taylor Group (Greenville, MS) 1998 | |
| 1150 | GR-12w | 1050 | Feb 17 86 | Nov 1 99 | To Cuban National Railway No. 51213 Dec 99 | |
| 1151 | GR-12w | 1051 | 1986 | Nov 9 98 | To Ouachita Railroad No. 65; To Central Columbiana & Pennsylvania No. 1151; To Hillman HIIX No. 1151 Jun 06 | |
| 1153 | GR-12w | 1053 | 1987 | Sep 30 99 | To Taylor Group (Greenville, MS) 1998; To Southern Railway of British Columbia No. 1202, to JLCX 2014 | |
| 1154 | GR-12w | 1054 | Oct 25 90 | Feb 29 00 | To Cuban National Railway No. 51217 Dec 99 | |
| 1155 | GR-12w | 1055 | Jan 28 91 | Oct 9 98 | To Dardanelle & Russellville No. 21; To Central Columbiana & Pennsylvania No. 1155; To Dardanelle & Russellville Jun 06, to Ouachita No. 1155 | |
| 1156 | GR-1w | 1056 | Jun 27 91 | Nov 1 99 | To Cuban National Railway No. 51214 Dec 99 | |
| 1159 | GR-12w | 1059 | Dec 31 83 | Nov 10 98 | To Dardanelle & Russellville No. 1159 1999, to Ouachita Railroad No, 1159, to OUCH 23 2020 | |
| 1160 | GR-12w | 1060 | Jun 10 85 | Feb 29 00 | To Cuban National Railway No. 51218 Dec 99 | |
| 1163 | GR-12w | 1063 | 1986 | 1063 | ||
| 1166 | GR-12w | 1066 | Jul 2 85 | Sep 17 99 | To Cuban National Railway No. 51215 Dec 99 | |
| 1167 | GR-12w | 1067 | 1986 | Sep 30 99 | To Taylor Group (Greenville, MS), to Ivaco No. 1167 | |
| 1169 | GR-12z | 1069 | 1987 | May 28 98 | To Taylor Group (Greenville, MS) 1998; To Southern Railway of British Columbia No. 1203, to JLCX 2014 | |
| 1170 | GR-12z | 1070 | Sep 21 90 | Sep 17 99 | To Taylor Group (Greenville, MS); To Southern Railway of British Columbia No. 1204; to JLCX 2014, To Western Rail (WA) 2015 | |
| 1171 | GR-12z | 1071 | Feb 28 90 | Jun 16 00 | To Cuban National Railway No. 51219 Dec 99 | |
| 1172 | GR-12z | 1072 | Jun 12 90 | Aug 19 99 | To Taylor Group (Greenville, MS); To Southern Railway of British Columbia No. 1205, to JLCX 2014 | |
| 1177 | GR-12z | 1077 | 1987 | Jan 2 06 | To Railpower (Edmonton, AB), scrapped 2008 | |
| 1178 | GR-12zc | 1078 | Jul 5 90 | 1078 | ||
| 1179 | GR-12zc | 1079 | Jan 23 86 | 1079 | To Alberta Railway Museum 2012 | |
| 1180 | GR-12zc | 1080 | Jan 31 90 | 1080 | To Cuban National Railway No. 51220 | |
| 1181 | GR-12zc | 1081 | Mar 27 90 | 1081 | To Cuban National Railway No. 51216 | |
| 1182 | GR-12zc | 1082 | May 4 90 | 1082 |