Siemens developed four-car electric multiple units called Class 450 on the Desiro platform. The vehicles, which were purchased from 2001 onwards, have an output of 1500 kW and draw their operating voltage from the side power rail next to the track. The maximum speed of the 127 vehicles is 160 km/h. The four-car units are used on London's busy suburban routes.
F17 slows down the locomotive slowly. With CV165 = value 0-5 you can switch between different brake squeals.
F29 and CV 168 = value 0 or 1, can switch between a "normal" or a "squeaking" wiper.
F9 can decrease the speed of the automatic drain trap valve by double-clicking it. The speed levels are fast, medium and slow.
| Key | Functions | Sound slots | Volume CVs | Volume values |
|---|
| F0 | front light | 29 | 483 | 25 |
| F1 | sound on/off | 1, 2, 5, 22, 32 | 259, 267, 291, 427, 507 | 90, 140, 50, 7, 230 |
| F2 | air horn (high) | 3 | 275 | 235 |
| F3 | air horn (low) | 4 | 283 | 200 |
| F4 | panto up/down | 14 | 363 | 80 |
| F5 | horn two tone | 16 | 379 | 200 |
| F6 | shunting mode | | | |
| F7 | flange squeal | 15 | 371 | 85 |
| F8 | AUX 1 | | | |
| F9 | automatic drain trap valve | 9 | 323 | 100 |
| F10 | conductor's signal | 10 | 331 | 85 |
| F11 | coupler clank | 8 | 315 | 110 |
| F12 | 3rd rail arcing sounds | 23 | 435 | 170 |
| F13 | parking brake | 30 | 491 | 100 |
| F14 | station announcements (random) | 7 | 307 | 128 |
| F15 | automatic warning system (aws bell) | 31 | 499 | 70 |
| F16 | open/close drivers door | 12 | 347 | 110 |
| F17 | brake function 1 (electro-pneumatic) | 18 | 395 | 65 |
| F18 | british station announcements #1 | 13 | 355 | 128 |
| F19 | british station announcements #2 | 17 | 387 | 128 |
| F20 | british station announcements #3 | 20 | 411 | 128 |
| F21 | british station announcements #4 | 24 | 443 | 128 |
| F22 | british station announcements #5 | 25 | 451 | 128 |
| F23 | automatic warning system (aws horn) | 28 | 475 | 70 |
| F24 | compressor | 6 | 299 | 128 |
| F25 | sanding valve | 11 | 339 | 25 |
| F26 | volume change | | | |
| F27 | open/close passenger door | 27 | 467 | 60 |
| F28 | air conditioning unit | 26 | 459 | 128 |
| F29 | windscreen wiper | 19 | 403 | 70 |
| F30 | | | | |
Make sure that index CV31 is set to 16 and index CV32 is set to 1 before changing a volume CV.