Entering, worried about movement in old vehicle (8,6)

I believe the answer is:

traction engine

I'm a little stuck... Click here to teach me more about this clue!

'entering worried about movement' is the definition.
The answer and definition can be both man-made objects as well as being singular nouns.
Maybe they are linked in a way I don't understand?

'in old vehicle' is the wordplay.
'in old' becomes 'traction' (I can't explain this - if you can you should believe this answer much more).
'vehicle' becomes 'engine' (engine is a kind of vehicle).
'traction'+'engine'='TRACTION-ENGINE'

Can you help me to learn more?

I've seen this clue in The Daily Express.

Want a hint initially instead of a full solution? Install my app