Controller of site safety (COSS) interview questions and

About the job itself

Why do you want to work as a controller of site safety (COSS)?
What drew you to this work, what you already know about it, and something from your past that shows you will be good at it.
What do you have that this job asks for?
Employers usually look for: PTS card (Sentinel), COSS competence. Say what you hold, with expiry dates where there are any, and bring the proof (cards, certificates, a portfolio): it is checked before you start.
What pay are you looking for?
A figure you can justify. Adverts for this job usually pay £32,000 to £42,000 a year, so check the advert, know your number and give it calmly.

Questions for rail & infrastructure

How do you stay safe working on or near the track?
You follow the safe system of work and the person in charge, every time.
Which competencies or cards do you hold?
The card, its competencies and expiry.
Are you happy with nights, weekends and travel?
An honest answer: most track work happens when trains do not run.
Are you ready for drug and alcohol testing?
Yes, and you understand why.
Tell me about working to a tight possession window.
Planning, teamwork, and handing back on time and safely.

The questions every interviewer asks

Why do you want this job, here?
That you looked at the employer: what they do, where, and one thing that appeals to you about them.
What would your last manager say about you?
Something they would actually say, with proof: "reliable, I covered the late shift for six months".
When could you start?
A straight answer. If you have notice to give, say how long; employers respect somebody who works their notice.
Where do you see yourself in a couple of years?
Ambition that fits the job: getting better at it, a ticket or qualification, perhaps leading a team.
Do you have any questions for us?
Always have two ready. See the list further down this page.

Questions to ask them

At the end you will be asked whether you have any questions. Have two ready:

What does a normal day or shift look like?
What would good work look like after the first three months?
Who would I work with, and who would I report to?
What training will I get at the start?
When can I expect to hear back, and what is the next step?

For the employer: what you must not ask

The same questions work from your side of the table. These do not, because UK law forbids them or makes them a risk:

Age, date of birth or when somebody left school. Age is a protected characteristic under the Equality Act 2010. Ask whether they meet any legal minimum age, nothing more.
Marriage, children, pregnancy or plans for a family. Protected characteristics. Ask everybody the same question about whether they can work the hours.
Health or sickness absence before a job offer. Section 60 of the Equality Act 2010 bans it, except to make adjustments for the interview, to check they can do a task that is intrinsic to the job, or for monitoring.
Religion, nationality or where somebody is "really" from. Protected characteristics. Check the right to work for every candidate in the same way, after the interview, not by guessing from a name or an accent.
Spent convictions. Under the Rehabilitation of Offenders Act 1974 a spent conviction need not be disclosed, except for roles exempt from the Act, where a standard or enhanced DBS check applies.
Trade union membership. Refusing work because somebody is or is not in a union is unlawful (Trade Union and Labour Relations (Consolidation) Act 1992, section 137).

Ask every candidate for the same job the same core questions, and write the answers down. It is fairer, and it is your best evidence if a decision is ever challenged.