Yes. Trailing tomatoes develop side shoots from between the main stem and
leaves. These should be pinched as soon as they are about an inch long.

Sorry Easyman but trailing tomatoes (Tumbler for example) can be left to self branch. It's the vinous ones that are grown up tall that need their side shoots pinched out.

If you pinch out trailing toms you won't get that many tomatoes on the plant. They will develop fruiting shoots from these - I grow both the trailing type (Tom Thumb) and cordon tomatoes. Cordon toms DO need to be pinched out however as side shoots will affect their fruiting. Trailing types however don't get pinched out.

I think Easyman was thinking that trailing meant the type you tie up. :-)