His engine sounds (Cecil Kerr's) are all aliased to the default Black 5 engine.
I do a lot of steam sound mods if you care to know some things. Most of the sounds can be changed to any engine you have in your inventory by editing the engine bin file to point to the engine sound you want to use. You can change just the whistle or the chuffs or the entire engine sounds. Right now I have the D&S using the chuffs from the PRR K4. I did this in a different way. Copied all the chuffs from the K4 sound folder to the \G-TraX\DSNG\Audio\RailVehicles\Steam\K27 folder. The names would be K4_CH_C1T1_Hi.dav, K4_CH_C1T1_Lo.dav etc etc. Open the K27_AudioControl.proxyxml and edit it to use these sounds. Replace C1T1_Hi.dav with K4_CH_C1T1_Hi.dav, and right on down the line till they all are changed to use the ones from the K4. Save the K27_AudioControl.proxyxml and drag it onto the serz.exe which will make a new K27_AudioControl.proxybin.
I probably could have explained this easier but it's really not all that hard to do.