Recommendations to hold up Mud wall in Garden

[Luckycharm]

I have a small hill on the side of my garden, I recently got a good bit of it dug out. There is solid mud wall but my worry is that this might collapse over time. Anyone have any recommendations of something to put up against this that might hold it up- A neighbour mentioned Railway sleepers?
Any other advice?

 

[mathepac]

... A neighbour mentioned Railway sleepers?
...

On their own they won't do much. You will need a proper retaining wall built. You can incoprate you sleepers into it but they will have to be anchored to something very solid.

 

[serotoninsid]

Depends on what exactly lies behind it - how high is it? what sort of constitution?

Gabion baskets might be an option if we are not talking about an engineered solution.