> An obstacle in the pipe How is an obstacle going to get into a vacuum sealed pipe? Unless there are parts literally falling off of the pods, I can't really s

> An obstacle in the pipe How is an obstacle going to get into a vacuum sealed pipe? Unless there are parts literally falling off of the pods, I can't really see this happening. > A misaligned tunnel wall due to shifting Earth This would most likely break the vacuum seal and be detected immediately. > Other pods ahead of it Seems easy to avoid. We don't typically hear about trains crashing into each other, so I don't see why we'd expect that to happen with pods.