Dang there goes my patent

Ok so since there’s a bunch of science nerds on here and I’m sleep deprived I’m gonna ask my dumb ftl question.

If you’re on a train and you walk towards the front of the train, your speed measured from outside of the train is the speed of the train (T) plus the speed of you walking (W).

So if there was a train inside of that train, and you walked inside of that, you’d go the speed of the outside train, plus the speed of the inside train, plus your own walking speed.

So what if we had a Russian nesting doll of trains, so that the inner most train was, from the outside, going as fast as light and you walked towards the front? Wouldn’t you be going faster than light if you measured your speed from the outside?

Didn’t come at me with how hard it would be to build a Russian nesting doll of super trains it’s a hypothetical and I’m tired.