Intersecting Rail lines / Crossovers

Can anyone confirm the following statement:

Finally, the grade crossing at the R-3 line near Bethayres station would have to be grade-separated, as federal law would forbid the past operation of a signalized at grade crossing of two rail lines

According to the author, federal law forbids two (passenger) rail lines from intersecting each other (i.e. at a 90degree crossover). When did this "rule" go into effect and what prompted it? With today's computerized railroads, I would think this would be a safe practice, but apparantly the FRA thinks otherwise.

I think someone is talking through their hat; Metropolitan Chicago alone probably has 50 diamonds used by passenger trains. There are many others throughout the midwest and south, but not many in the east or far west. It certainly isn't the first choice if either line has heavy traffic, but I can't believe it's more than a "wish list" point...

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In signalling/dispatching parlance, a "crossover" refers to two switches allowing passage between two paralell tracks; the intersection of two rail lines at grade would be referred to as a "crossing' or "diamond".

In rare instances, if the angle of the crossing was relatively slight, movement between the two lines could sometimes be accomplished merely by moving the diamond itself.

Constructing a new diamond is most certainly legal, and even best practice in some places. They've been installed fresh in quite a lot of light rail systems and some transit systems. Of course, for a mainline, it would nowadays have to be *fully* signalized, to an "interlocking" degree of signalization; if one line required cab signals, cab signals would have to be used on *both* lines, for instance. This might create problems -- a lot of "grandfathered" diamonds get away with what is now fairly substandard signalling, including entirely unsignalled diamonds, "stop within line of sight", diamonds protected with crossing gates, and other weirdness, most of which would probably be prohibited in new builds.

On the other hand, I'm wondering about the phrasing. "the past operation of a signalized at grade crossing of two rail lines" could refer to a pedestrian or automobile crossing of a pair of rail lines, controlled by a traffic signal. Those *are* illegal; new at-grade road/rail crossings require gates and flashers (in most cases), and it's severely discouraged (though still legal) to have more than a single track crossing a road at grade. It could well be prohibited to install two tracks running at different angles in a single road grade crossing.

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