As many of you will be aware I like Bulleid Pacifics
The Southern Region used to fit white disc head-codes to their loco's during the day, and lamps at night, which depicted the route the loco was on. If you have a multi-hole hole punch these can be simply made from .05mm plasticard, and stuck to the various lamp irons on the front of the loco with a dab of PVA. If you Google "Southern Region Headcodes" you will find several sites giving the various formations these head-codes can be set up as. A paper hole-punch used for filling a ring binder makes the disc a little larger than ideal, but I doubt many would notice. The discs just add a little more realism to your loco. The "dust" is an optional extra
The picture depicts West Country Class 34040 Crewkerne with headcodes for a Portsmouth/Southsea to Salisbury via Eastleigh train.
IMG_1054 by
Barry Clayton, on Flickr