Even grass is capable of upsetting ballast, let alone bushes

Hi All. Have you seen a Railway Yard covered in grass? Especially when the weed killer has been sprayed manually or by train  It is good to have ground cover on a model Railway, it’s much better than plain wood , one may find it around gate posts or Buffer-stops. Please advise thank you.  Best wishes Kevin 

I think you've answered your own question Kevin - you rasrely saw weeds or grass after the weedkillers had been around.

As you say, around gateposts and dead bits of track behind buffers etc. would have had some grass but I doubt many big weeds.  Most weeds are broad-leafed plants and as such, are easy to kill with simple chemicals.  Grass type weeds are much harder to kill off.

In yards, there would be lots of foot fall in those days so not much hope for plant life ……………

I'd just have green stuff around the edges where people wouldn't go.

It depends on the period you're modelling. 
Up To ww2 the majority of yards were well kept, with the lack of manpower from ww2, everything got neglected . If the yard was busy the somewhat poisonous ash and oils,  kept the yards clear but it grew along the edges unless it had been sprayed.. If the line was slated for closure,  then a lot of routine maintenance just stopped and grass would get everywhere.. 

Hi Petermac.  Thank you for your reply. I suppose apart from ballast early on it could have been ash , Unless you could give me some different ideas.Best wishes Kevin 

Hi The Q . Thank you for your reply. I am roughly modelling the transition from steam to diesel. With an electric loco thrown in for good measure. But when I was at School I didn’t have the money to go train spotting except on the annual holiday , by then I think the trains from Waterloo to Portsmouth for the Isle of Wight were Nelsons.   Best wishes Kevin 

From memory Kevin, in steam, and indeed, early diesel days, the yards were ash and clinker well packed by the various road and foot traffic.  Almost no similarity to ballast as we understand it.  Remember, people, horses and then vehicles had to walk on these yards so the surface had to be well packed.  In the loco service yards, the ballast would have had a good coating of ash and clinker well flattened so again, little evidence of stone ballast.

I do remember the surface was usually almost level with the rail tops to avoid people tripping over the rails.  Sometimes the part between the rails wasn't quite so full so one stepped down slightly onto where the sleepers would be, had they not been buried in whatever they used for surfacing.

In steam days particularly, there was plenty of material available for surfacing simply from cleaning the fireboxes and grates etc.