The 19-year-old had been going with companions on the Jubilee line in south-east London on 21 October when he was verbally manhandled by two men.
One of them place him in a wrestling hold while the other took his telephone and debilitated to cut him. He was then choked until the point that he said sorry for being gay.
The British Transport Police (BTP) said “detest wrongdoing would not go on without serious consequences”.
The gathering that incorporated the casualty were wearing extravagant dress and had been going between West Ham and North Greenwich when the assault happened.
After the men discharged the young person they gave him back his telephone yet got into a battle with whatever remains of the gathering, police said.
A 25-year-old lady endured wounding after she was punched and pushed to the ground.
In an announcement, the BTP stated: “We won’t endure conduct where somebody is focused on in light of the fact that they are seen to appear as something else, or made to feel awkward on their voyage.”