A transgender female city bus driver plans to sue the MTA after allegedly being assaulted and told to use the mens’ room, according to a new legal filing.

Ernesto “Nana” Mangual, 36, claims another bus driver attacked her inside a women’s locker room at the Eastchester Bus Depot in the Bronx March 17, police said.

Longtime MTA worker Sonia Rivera, 60, was initially charged with yelling an anti-LGBTQ slur at Mangual and striking her in the face, the NYPD confirmed.

However, a judge later granted an adjournment in contemplation of dismissal in the case “after an investigation found no evidence of assault,” said Patrice O’Shaughnessy, a spokeswoman for Bronx District Attorney Darcel Clark.

Mangual went out on workers compensation in late March, her lawyer said.

On June 6, she filed a charge of discrimination with the state Equal Employment opportunity commission, documents show.

Mangual filed a notice of claim with the city on June 7.

“My client’s world is shattered all because she is transgender. The MTA let her down,” Mangual’s attorney, Christopher Berlingieri, who is poised to file a $10 million suit in Manhattan Federal Court, told The Post.

Added Berlingieri: “We want the MTA to provide gender-neutral bathrooms and anti-discrimination training focusing on transgender equality.”

The MTA would not address the pending litigation or Rivera’s status.

“The MTA does not tolerate violence or discrimination of any kind in the workplace and takes allegations of this nature very seriously,” said spokesman Eugene Resnick. Rivera could not be reached for comment.