The law of unintended consequences is just about to kick in.
A sqn ldr and above is entitled to first class rail travel. A commissioned officer below the rank of sqn ldr is ordinarily entitled only to a second class ticket. However it is is necessary for him to travel in uniform, ie be seen to be an officer, then he is entitled to be issued with a first class ticket.
Now which budget manager is going to say you must wear civies not withstanding the IBN?
PS, while my budman may not have executive responsibilities she still guards the shelks. She issued me with a 2nd class warrant as that is what they always issued. I upgraded myself anyway so they still paid.