The spikes don't really hold anything down, weight does that. Just ride along a stretch of track and see how many spikes are sticking up.
The spikes keep things in place. Since there are more forces at work in a curve, you will see four spikes used on curved track. The tie plates are usually bigger too. Also, notice that tie plate has a wide groove for the rail to lay in.
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There are several tie plate designs depending on what weight rail is used. There are some old pictures online of yard tracks in the 40's and 50's that show light weight rail with no tie plates but this isn't the case anymore. It was very common at the turn of the last century and on some narrow gauge and of course logging railroads. At curves and grade crossings you may see 4 spikes used per plate and occasionally you'll see more as spikes may be holding the tie plate down to the tie in addition to the spikes used to hold the rail down. There is a new style of tie plate that is getting more an more common that uses clips instead of spikes. These were mostly seen on concrete ties for a while but are getting used more and more on wood ties as well. We have a few places here in Houston that use them.
fredswain There is a new style of tie plate that is getting more an more common that uses clips instead of spikes. These were mostly seen on concrete ties for a while but are getting used more and more on wood ties as well.
Sounds like Pandrol clips.
The "pandrol" plates are still spiked to the ties. The clips lock the rail in place.
I still wonder why the U. S. still uses spike and not screws. Walk along the track and seen all the popped spikes. You see a several inch gap between the rail and tie. That causes the bounce in the cars. Then that beats the rail head down and in turn separates the rail and ties even more.
It would not be a hard transition. present tie plates could be drilled to the round hole.
Yes I know the equipment change from hammer to twist to screw. Not a big change. just cost.
During my visit to Ny. Ny Nov. 7 to 13 2010. I rode the subway several times. Yesterday I rode to Coney Island. Along the way I noticed the clip on -pandrol- rail locks. They were held down with screws. The screw was approx. 3/4 dia and had a thread of about 4 inches. It had a square head of about 3/4sq and 1 inch high. Sometimes I seen 1, 2 , and three screws into ties. all the plates had 3 holes.