Narrow plates

The examples of tie plates that were used on the Uintah Railway, were of three verieties (as found on the right of way) at this point. Most were embossed with "Western" or some other name that I forgot, as I've tossed these back on the dirt, but I think that for the most part they were four holes on them for spikes. The other two were embossed "Uintah RR no.1" or Uintah RR no.2". Both of these are three holes tie plates, the no.1's are shorter in total length that the no.2's. All of the examples of the "Uintah" embossed plates have been on the Dragon Mine branch of the Uintah, which means that they were probably installed before 1911, most likely in the original building of the railroad in 1904. Does not explain though, why they are only found on that short branch of the RR, and on no other portion of the line?