Have you heard those angry Transport Workers Union ads slamming MTA Chairman Pat Foye? They’re a great sign that Foye is doing his job.

The TWU contract expired in May, and straphangers and bus riders need the new deal to include provisions that allow the MTA to deliver better service.

But the union doesn’t want to give, hence its huge radio buy of ads calling for an Oct. 30 rally outside MTA headquarters.

The ads have one thing right: Transport workers have every right to demand the MTA (and the NYPD) protect them from being spat on, threatened and assaulted. Nor should their union need to make any concessions to get that protection.

But the average TWU member earns more than his or her private-sector equivalent, and far more than the average New Yorker — and with better benefits.

Meanwhile, contract rules make it brutally hard for the MTA to fight overtime and pension fraud. And some work rules are just outdated. The MTA shouldn’t have to deliver fat pay hikes just so it can even experiment with running heavily automated trains with a single worker. Nor so that cleaning crews will use cleansers that actually remove the smell of urine.

The agency’s operating budget is more than $400 million in the red, and headed to shortfalls over $1 billion a year by 2022.

Foye is willing to let union members share in the savings from contract changes, but the public needs him to get those changes. Otherwise, the transit system is headed back to decay — dragging the whole city with it.