Construction progress was halted recently as the rail spikes refused to hold the rail securely to the ties. Pre-drilling an undersize hole for the spike to prevent splitting seemed to work but there was not enough grip to hold the rail.
In the past I have used Shinohara code 70 spikes which I had purchased some 30 years ago and had literally thousands of them. They are work very well when hand laying code 70 rail to ties on a fixed roadbed but spiking rail to a splined trestle bridge beam is another problem unto itself.
Several different sizes of spike were tested and used including Micro Engineering Micro Spikes measuring 4.5mm in length and .28mm in diameter, Micro Engineering Medium Spikes measuring 9.0mm in length and 0.8mm in diameter and Peco Rail Spikes measuring 14mm in length and 0.8mm in diameter.
The photo above shows the 3 sizes of spikes plus a prototype spike…! (from the White Pass & Yukon Railway in Alaska).