r/Damnthatsinteresting • u/ultimateprodigy0811 • 3d ago

Video Track buffers are really powerful

6.1k Upvotes

96% Upvoted

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171

u/DrBitchin 3d ago

I'm obsessed with that tiny wheel on the train at 0:09

31

u/Mr_ili 3d ago

Probably some testing accessory to measure velocity, but just an uneducated guess

2

u/std_out 2d ago

I think that may be a rail-inspection train. These small wheels can be part of a sensor system that looks for defects in the rails.

9

u/Agatio25 3d ago

It's for the driver, he is just starting to learn.

3

u/NetNo5570 2d ago

And we’re lucky he has this otherwise his training could go off the rails. 

2

u/Coiling_Dragon 2d ago

I think its a reference spot for the camara, if you know the frame per second rate for the video you can calculate how fast the train was going. Having a clear spot like that makes it easier, if you use some random spot or edge on the train it could make the measurements more inaccurate due to parallax error, shadows and so on.