All signalling jobs if you are recruited from the street are apprentiships now.
If it is a a future ops/or one of the talent pools where your trained but no guarantee of a job at the end, You’ll be required/encouraged to apply for jobs whilst training and during the 12-18months of the contract.
NWR won’t want to speaks that amount of money training you up (tens of thousands of pounds) and get rid you at the end.. they will want you to apply and get a job with the company. But it will down to you to be proactive, and find another signalling role