Christine wrote:

If a buckle is likely to occur it is where there is
a weakness in the ballast formation and then both rails buckle out
with sleepers in tacked.

Did you meant to write "intact"? Even so, I don't understand this.
Please explain further.

--
John Ray, London UK.

Mail to mefp49 is unlikely to be read. I can be contacted at xcf70 (same
ISP).