[double00]

I have made a similar crossing by use of thick 2mm card cut to fit between and either sides of the rail and painted grey.
Remember to leave sufficient space between each rail and board to avoid fouling of rolling stock flanged wheels and the undersides of rolling stock.

 

[double00]

dr5euss - I checked my level crossings made from 2mm card, and the card pieces are slightly below level of the rails.
I found this necessary as some of my diesel locomotives add-ons were fouling the level crossing card pieces.