Why did Panama REDUCE 5' to 4'8.5"?

We were discussing the Blue signal lights the original poster saw in Panama . Please read the whole thread , though parts of it seem to have gone missing .

There was a question about blue signals in the original post ("They have dwarf signals with BLUE color. What does blue mean?"). There had already been one response on the meaning of blue/purple signals in New Zealand and I just thought the original poster might be interested to know their meaning elsewhere in the world.

The KCS operation on hte Panama Railway uses (or used the last time I checked) ex Amtrak F40 locomotives, and probably other rolling stock imported from the US. They use the F40s' head end power supply to power refrigeration equipment on containers, which I guess is how containers are cooled on ships, too. That's a pretty specialized set of equipment and would have cost an arm and a leg to buy new or to regage.