What caused the deadly train mishap in Maharashtra involving Pushpak Express passengers?

Panic erupted aboard the Lucknow-Mumbai Pushpak Express on Monday afternoon near Pachora station in Maharashtra's Jalgaon district. Sparks were spotted emanating from the train's wheels after the brakes were applied, prompting alarmed passengers to pull the emergency chain, witnesses reported.
Several passengers disembarked in haste, with some jumping onto the adjacent tracks. Tragically, at least 12 were struck and killed by the Karnataka Express, which was passing at high speed on the parallel track. Eyewitness Salman Pathan, a resident of Pachora, described the horrific scene of mutilated bodies scattered along the tracks, including the headless body of a man and a woman grieving inconsolably for her husband.
Accounts from the scene
"Passengers panicked when sparks flew from the wheels," a passenger told a Marathi news channel. "Some pulled the emergency chain and got down, resulting in the tragedy. I saw at least two passengers come under the wheels of the Karnataka Express."
Officials stated that visuals from the site showed mutilated body parts along the railway track, with many passengers seen descending a slope after the train halted.
A senior railway official explained that preliminary investigations pointed to a potential hot axle' or brake-binding' issue in one of the general coaches of the Pushpak Express. "The panic caused passengers to pull the chain, and some disembarked, leading to the tragedy as the Karnataka Express passed," the official said.
Aid from locals
Residents of nearby villages rushed to the scene to provide assistance. Despite the horrifying incident, the Pushpak Express resumed its journey after more than an hour.
With PTI inputs