If you look at the first picture there is actually something that looks like spikes but only one per sleeper, I would expect to per sleeper on at least one side of the rail. Shoes? US narrow gauge lines where usually simple built, the rails would normally be spiked directly on the sleepers.
This is normal US practice for all except for Heavy Duty/High Speed Main Lines. Certainly for Branch and secondary lines, this is the reason 4 wheel stock was replaced very early on with bogie stock (to reduce derailments!). Following is a photo from a Rock Island pictorial book Multi railroad used track near St. Paul, Minnesota. Check the near track and then that under the train!
