It looks quite high on visualizations, possibly standard ventilators like those in road tunnels, that just provoke airflow through tunnel will be sufficient. It

It looks quite high on visualizations, possibly standard ventilators like those in road tunnels, that just provoke airflow through tunnel will be sufficient. It's "just" 1,7km long. Of course pollution will be high, but traffic low, compared to cars. It seems like something that may not require any new revolutionary systems, just old school solid engineering.