There can be.
LUZ - locomotives (diesel or electric, it depends)
E-LUZ - electric locomotives
OSOB - passenger trains
POSP - passenger InterCity trains
PAS - passenger trains
TOW - freight trains
SM42 - for SM42 (diesel) locomotives
SM/SN, SPAL etc. - for all diesel vehicles
ALL - for every type of vehicles
EZT - spawn exclusive for EMUs (like EN57, EN71)
SZT - spawn exclusive for DMUs (like SN81)
<any other name> - most often you can spawn everything here
If I've forgotten anything here, let me know. I'll edit this post.