LOL - Steve, I sence you see I'm strugling and a bit out of my depth

I would like to use 4 channels in total so I can control 4 trains all independantly, but I'm not bothered if I need to use two chips.

I have at my disposal the following PICs:

16F84A
16F873A
16F628A
16F676
16F688
16F877A
16F684
18F2550
12F675
18F4550

Thanks