Unearthed a few unknown glass pieces

[How Lucky]

Unearthed a few glass pieces today in an old railroad depot foundation. I have no idea what they were used for. I am hoping someone can help me out.

Also found a few 4 1/2" railroad spikes. What would a spike that small be used for?

 

[Professor of Engineering]

Nice finds, congrats!

 

[Digger RJ]

Nice!!! Congrats!!!

 

[A2coins]

Look like some type of insulaters good job

 

[vpnavy]

I searched Google and found similar (close anyway - maybe miner cart tracks) spikes - See: The spikes used to fasten T-shaped railroad track to wooden...

 

[How Lucky]

Some thoughts on the glass.
The nobs to me, appears to look like they would have been inserted into some kind of panel or sign. Where a single light source from within, would illuminate all the the nobs.
Just throwing out some ideas. I hope that someone may have seen something like this before.