Silicon Valley has had its share of squabbles among start-up founders — just look at Facebook and Twitter. But few are stranger than the legal battle taking place at Hyperloop One.

The high-profile Los Angeles start-up is building a high-speed train that gets propelled through a tube faster than the speed of sound — an idea that was proposed by Elon Musk several years ago, when he challenged fellow entrepreneurs everywhere to build it.

But even as it aims to transform the future of transportation, the company has been embroiled since July in a bitter lawsuit, brought by four former executives, that gets uglier by the day.

The plaintiffs, one of whom is a co-founder, claimed the company was nepotistic and grossly mismanaged. When they tried to fix the problems, they said they were wrongfully fired and harassed by their former colleagues. The company’s chief technology officer, Brogan BamBrogan, even claimed a noose was left on his desk as a threat, forcing him to seek a restraining order against a former colleague with whom he was once close.

Company officials fired back, claiming BamBrogan and the other executives had been secretly plotting a takeover coup. When they failed, the company alleges, the former executives made plans to steal trade secrets and build a rival company, going as far as registering a domain name, hyperlooptoo.com.

The founders also alleged that the disgruntled employees created a fake Twitter account, which they used to splatter insults on their former boss, according to the complaint. Now Hyperloop One is doubling down. In a new legal salvo filed on Wednesday, the company said it had uncovered more evidence of the coup. According to the filing, in California Superior Court in Los Angeles, the group held secret meetings in BamBrogan’s garage. There, they compiled a list of colleagues to poach for their competing venture and began efforts to steal Hyperloop One’s patents. They also discussed raising millions of dollars to fight their former employer in court, the complaint said.

But Justin T. Berger, an attorney for the former executives, said that if they wanted to form their own company, they simply would have left.

“This filing is nothing more than a thinly veiled publicity stunt,” he said.

The suit comes at a moment when the hyperloop, which would allow commuters to zip between San Francisco and Los Angeles in 30 minutes or less, is starting to get some traction. The start-up has signed early agreements to begin exploring the technology in Dubai, and is conducting feasibility studies at five locations around the world, including the ports of Los Angeles and Long Beach. The case came shortly after a major test of the technology in the Nevada desert.

“Today’s filing sheds even more light on the attempted illegal coup by this Gang of Four, and demonstrates the extensive plans they took to form a competing company,” Hyperloop One’s attorney, Orin Snyder, said in an emailed statement on Wednesday. “When their plans blew up in their face, they staged a propaganda campaign designed to harm the company.”

Snyder, who represented Facebook during a bitter dispute early on, insisted the lawsuit would not derail Hyperloop One’s progress. He said squabbles tend to happen when a start-up is on the rise and people crave more compensation. In court filings, the founders denied that a noose was left on BamBrogan’s desk. Rather, it was a lasso, they said, placed near a cowboy hat BamBrogan kept on his desk.