And, realistically, that's perfectly safe enough. A lot safer than crossing a motorway style 70mph dual carriageway on the level, which you can do. Whereas walking across the WCML on the level is rather less so. OK, you could potentially trip over the rail if you really weren't careful, but walking across, say, the Cambrian in the middle of nowhere, provided there's a good sightline, is no more dangerous than walking across the barrow crossing at Tywyn right in front of the train (which feels
really odd, I must admit, but is allowed despite there being road access to both sides).
The UK takes the absolutist line of thou shalt never walk on the railway, but most other countries don't - the UK is well out of line with the "standard" on this one.
One exception - segregated tramways, where crossings are basically always on the level. And walking across the Cambs busway feels weird too!