The 4-CIG, later Class 421, was the standard Southern Region long distance 750V DC 4-car EMU from the late '60s, used across the region and particularly on the Central division. Safety concerns over slam-door stock led to their replacement by new sliding door stock during the first few years of this century.
- Class 158, 159
- Class 444, 450
- Class 455, 456
- Class 165, 166
- Class 220, 221, 222
- Class 458
- Class 800 - 810
- Class 491 4TC
- Class 345
- Class 390
- Class 397
- Class 701
- Class 375, 377, 379, 387
- Class 168 & 170-172
- Class 319, 769
- Class 185
- Class 325
- Class 350
- Class 150
- Class 707
- Class 180
- Class 156
- Class 423 4-VEP
- Class 442
- Class 320, 321, 322