While the train is in motion, we fall to the same place when we jump in the wagon, but when we do this on the train, we fall to a different place. Why?
(see law of inertia)
I am throwing the train while moving in the train, if it goes at a speed of 150 km per hour, you will go at a speed of 150 km. because you are tied to the train by the feet. So what happens if you jump in the train? You fall where you are. because you jump in a place where there is almost no air friction, so you fall on the same place.
So why do you fall in the same place? remember, you were traveling with the train at a speed of 150 km, so even if you disconnect from the train, you will continue to go at a speed of 150 km.
If that's the case, we're going at the speed of the train for a while, even if we disconnect. Why do the objects we throw from the glass stick to the ground like a lap? Or why do we fly when we jump on the train instead of inside it?
because there is friction outside the train. Air friction reduces your speed very quickly from 150 km/h. You can think of the friction difference as follows: try to take your hand forward in the train, and try to take it forward by taking it out of the window.
If your speed suddenly decreased when you cut off your connection with a moving object, when I let go of a spear from the front of the train, it would pass through all the people at a speed of 150 km and come out at the very back.
Let me add a little:
According to Newton's first law of inertia, an object maintains its state of motion unless an external force acts.
According to Newton's second law, another object in a moving object is under the influence of the main body it is in. that is, a fly flying on a moving bus will normally move inside the bus even when the bus travels at a speed of 120 km/h. In order to stay in the bus or not to stick to the back of the bus, a fly does not need to accelerate to 120 km, which is not possible for a fly to speed that much anyway.
As in the event I quoted above, as long as the speed remains constant, there is a total movement.
Since the air in the train moves with you and your speeds are the same, you have to land on the same place at a constant speed and incline. If you jump on the wagon, the air is fixed (earth) and the wagon slides under it because the train is moving. If there is the same wind as the train in the opposite direction to the train, you will fall to the same place.
Most of what you wrote was written roughly without considering the factors. (friction, slope, etc.)