I have used wooden ties since 1978 for certain parts of my pike which are still in service although I have started on those portions a tie replacement program since 2016. My track lies on a concrete base (pre cast concrete sidewalk borders) and I use oak (10mmX10mm. oak sections bought at the hardware store) ties dreched in mixture of creosote, used crank case oil and a bit of tar paint so they stay black (otherwise they turn grey after one winter). The brass rail was clipped to these by a brass clip not manufactured any more this fitted into a slot in the tie. I had to recreosote about every two years. My climate is very humid and clayish soil (hence the concrete base) I use loose ballast which is over scale size because I cannot glue this track down. My scratch built pointwork uses the same rail and ties but I had to drill small holes in the rail base to hold it down with brass estuchion pins. This held out nicely for a few years and then the brass pins started to get pushed out by the incessant alternance between humidity (in winter) and the dryness in summer.
The track is rawl plugged with brass screws every foot or as needed.
The problem of the brass pins comming out brought about a solution which has helped me renovate my track since: I use coper wire of 1,5mm diameter which I strip and bend into a U shape sort of staple. I mark out on the new ties where to drill and then insert from the bottom of the tie these U shaped clips. These are then clipped a few mm proud of the ties and then bent over with pliers to hold the rail to the tie firmly. I did this every 4 or 5 ties and at strategic positions on my pointwork (at the frog, where the switch rails separate from the switch blades etc.) and this made my switchwork much more reliable. I then was going into modeling Pennsylvania railroad and descided to use this technique to renovate my 34 years old track by inserting a new tie between every old one, so as to make my track look more like US track which has a much tighter tie spacing. This indeed renovated my track very nicely, and should outlive me. I have done this over the last three years about 15-20' at a time each summer.
Oak which is readily available in hardware stores over here in France in 10mm X 10mm or 8mm X 9mm, which is even more to scale. Seems to last about thirty years if creosoted regularly, even in a very humid environment. The overscale ballast is because scale ballast gets blown away by the rain drops. On the outer track where I used tenmille plastic base track I have glued down scale ballast (I buy it in big bags from an aquarium supplier) but it is often invaded by moss. Since two years I have succesfully combated moss using extruded plastic (most likely PVC) boards made for easy renovation of bathrooms and also sold in hardware stores over here. It covers the track and: No more moss! It also protects the track which otherwise would be drenched all winter here.