If you were given a caution by transport police will it show up on your CRB check?

Yes a caution from the transport police will show up on a dbs check for 6 years (2 years if you were under 18 when cautioned). Once that time period has passed, it will only continue to show if one of the following is true:

• the offence is on the DBS 'List of offences that will never be filtered'
  

• it is an enhanced DBS check and the police reasonably believe the caution is relevant to a recruitment decision.