Railway sleepers

Maybe someone on here has used them for raised beds etc and can advise?
I have a retired horse who lives in our field which has a field shelter. Under normal conditions and since we moved here 13 years ago, the field shelter has been bone dry that is until about 2 weeks ago. Having endured torrential non stop rain for weeks the ground in front of the field shelter went past muddy into what looks like Mushroom soup and water began to drain into the shelter. The shelter now resembles an indoor swimming pool...nice not!
I am thinking about getting a couple of railway sleepers, digging down and burying say about 1/2 of them width wise across the entrance to the shelter to make a bit of a barrier to stop water draining into the shelter. I'd need 2 I think as the width of the shelter is just under 4 metres. The horse would then have to step over the sleeper to get into the shelter but that's no big deal, hell he used to show jump fences of 1.3mtrs so think he can manage a step over! My question is what to hold the sleepers in place so the horse doesn't dislodge them. I have seen metal spikes holding sleepers back but these would not be suitable as knowing his lordship he'd go and cut himself on them. I wondered about short stobs?
It would be really helpful if anybody had any knowledge or ideas as to what to use which would work and wouldn't cost much. Thanks.

 

A few wooden fence post, you can get half round ones, one hammered in both sides of the sleeper and cut of to the height of sleeper

 

I was going to say that,....... but it seemed too easy

 

I like easy a lot. I'll pop down to the fencing contractors and see if they can sell me/tell me where I can get some 1/2 round ones. I didn't know you can even get such things! Many thanks Jiffy and Pete.I have a big heavy mallet for bashing stuff in, just not too sure I still have the muscles to do it. Daughter goes and lifts weights at a gym, while she's not very big maybe if I smile sweetly she'll be able to batter them in.

 

I was thinking of the split chestnut type stuff.

 

The sleepers will be slippery as he11 when they are wet

 

Yes @whis4ey, however I'm planning on digging then in on their edges so the horse will not be walking on them just stepping over. He is "4 wheel drive" and therefore shouldn't have a problem...famous last words, horses have zero self preservation and can manage to hurt themselves with monotonous regularity even after you have tried your very best to remove all possible dangers!

 

Now that IS a great idea @shiney, thanks. The only snag is that the entrance is wider than most sleepers (approx 4mtrs +) but even so we could butt an end of each sleeper, (will need 2 and then cut 1 to size) a la the photo (where in earth did you find that?) and that would mean I wouldn't need so many short fence posts. I have sourced some sleepers and have found out where I can get some short fence posts now just need to wait for daughter's BF to go and pick the sleepers up, he's got a long wheel based van which should cope ok. at least we have been dry for 4 days now and the " indoor swimming pool" has dried up much to the horse's pleasure no doubt.