Well, if you look worldwide, 1.5kv is on the way out for mainline applications, though it's growing for LRT. There are reasons why - it's one of the more constrained systems out there, and conversion upward to 3kv (which has had excellent results in the US and abroad) isn't that hard with modern inverter stuff. Practically, it's something Metra/NICTD should look at for a few reasons:
* Rolling stock weight in the US is out of control. Heavy trains require more power to accelerate, and high acceleration is key when station spacing is tight. AC inverters will help but they're not magic. Going to a stainless body should help too, but again, no magic here.
* Doubling the line voltage automatically cuts the current in 1/2.
* Less current means lower losses - it's why third rail sucks so much for long distances and high speeds - the current goes way too high, meaning tight substation spacing.
* Even with heavy (read: expensive) gauge trolley wire, you still have big losses. Wires have resistance, which is why you need multiple substations in the first place (if wires were all 0 ohm, you'd need one big substation in one spot and no others). A higher voltage means less drop which means more power at the ends of the circuit.
* The incremental costs of building 1.5/3kv equipment are nil today. Just a somewhat different converter for the DC link.
* 3kv gives you longer substation spacing, i.e. lower cost PLUS it means a train's more likely to be nearby, thus meaning regeneration is actually worth the investment vs replacing every substation on the line. Regen alone is a big money saver.
* The costs of doubling the voltage at this end are low - clearences are generally already good enough, and you can change over as part of a natural replacement cycle. Going to high voltage AC would be a huge outlay - you'd have to replace the entire system as NJT did.
There's no reason to go rip out the existing system. But as subs get replaced, and things get changed out, it makes sense to plan for an upgrade - the costs are minimal and the advantages are big.
1.5kv was a great idea back when the IC electrified - the other choices were third rail (bad), high voltage AC (still unproven and developing, plus it then required 25hz power), or DC at some other voltage. There were no 3kv MUs in the 20's. On top of which, 1.5kv was already popular with interurbans and streetcar lines (though ironically the South Shore was AC at 2 voltages) - a standard GE or Westinghouse system existed for the car equipment.
Over the years, technology caught up. 3kv MUs appeared in NJ and worldwide, rectifier technology matured at a fast pace, more recent power semiconductors made things even better. Just like the NEC's 25hz system is a techlogical dinosaur with lots of baggage, the 1.5kv system's a dinosaur too. It served it's purpose, but today's demands of very heavy cars and the need to have high acceleration to stay competitive with driving, mean it's going to get stretched to the limit, which isn't a good thing - witness the LIRR's issues of recent years.
It's better than diesel operation, that's for sure...
Last time I was on ME, I recall the train getting up around 60mph, but this was a few years ago. The acceleration wasn't that great on the Highliners though, especially given the remakably tight station spacing...
