25 replies to this topic

[jcepler1]

I've heard that 66/67 being pulled by a P42 is quite common, to allow for catenary work all over the NEC.

The problem with NJ Transit's ALP-45D (or one of the problems) is that being super heavy, it has to travel slower over the Portal Bridge. I was told that a train with the old E-60 Electric locomotive would take up 1.75 train slots because of this.
Having those locomotives run into Penn Station would cut down on the number of slots, and the tunnels are already pretty near capacity. But I assume that they will be certified eventually.

Personally, I don't understand how Amtrak/ LIRR/ MNR have had diesel /3rd rail dual mode engines for decades, but an diesel/ catenary dual mode engine is new, untested, and revolutionary.

[afigg]

I'm passing through Dave's backyard right now (Kingston, RI) as I type this. How frequently does catenary work happen in RI and CT? I ask because as I was departing South Station this morning, I watched 66 pull in with another P42DC. I understand now that it's common, but doesn't the section south of NY need it more right now since so much effort has been put in north of there?

All of the catenary east/north of New Haven is fairly new, so they are not likely doing much direct work on the existing catenary there. There are a number of projects underway in eastern CT on the Shore Line East route. Niantic River bridge replacement, replacement of a bridge over Rt. 1 in Branford, adding catenary to the passing sidings at the stations so CT can switch SLE service to M-8 equipment in place of diesel locomotives. Don't know when they will start on the 1.5 miles of 3rd track and high level platforms at the Kingston RI station. With little traffic on the SLE line late at night, likely easier and safer to turn the catenary off than to work around live catenary.

CT DOT is replacing the catenary on the New Haven line in western CT with constant tension. But this is a long term project that has been underway since the early 90s and won't be completed until around 2017.

The project to replace the catenary on the 24 mile segment from Morrisville PA to New Brunswick NJ is a separate project and, IIRC, is expected to start next year.

[AlanB]

Personally, I don't understand how Amtrak/ LIRR/ MNR have had diesel /3rd rail dual mode engines for decades, but an diesel/ catenary dual mode engine is new, untested, and revolutionary.

Well part of it is simply the fact that there isn't a huge demand for such a locomotive. Amtrak doesn't absolutely need one, which leaves only NJT really having a need for such an engine here in the US.

Then, and PRR60 or others may correct me, but it's my understanding that one needs a much bigger transformer to convert 11KV into traction power vs. converting 700V into traction power. And one of the biggest components of a transformer is iron, which is very heavy. Need a bigger transformer? Then you need more iron and more space. An engine has both a space limitation and a weight limitation.

So trying to figure out how to shoehorn both a transformer and a diesel engine into the body of the engine and not going over the weight limits isn't exactly easy. Even the P32 AC-DM's have a smaller diesel engine than the P42 because of the extra room and weight needed for converting third rail power. The P32's have a 12 cylinder engine, while the P40/42's have a 16 cylinder engine.

[PRR 60]

Personally, I don't understand how Amtrak/ LIRR/ MNR have had diesel /3rd rail dual mode engines for decades, but an diesel/ catenary dual mode engine is new, untested, and revolutionary.

Well part of it is simply the fact that there isn't a huge demand for such a locomotive. Amtrak doesn't absolutely need one, which leaves only NJT really having a need for such an engine here in the US.

Then, and PRR60 or others may correct me, but it's my understanding that one needs a much bigger transformer to convert 11KV into traction power vs. converting 700V into traction power. And one of the biggest components of a transformer is iron, which is very heavy. Need a bigger transformer? Then you need more iron and more space. An engine has both a space limitation and a weight limitation.

So trying to figure out how to shoehorn both a transformer and a diesel engine into the body of the engine and not going over the weight limits isn't exactly easy. Even the P32 AC-DM's have a smaller diesel engine than the P42 because of the extra room and weight needed for converting third rail power. The P32's have a 12 cylinder engine, while the P40/42's have a 16 cylinder engine.

Yep, that's right.

The 11kV or 25kV catenary voltage is great for transmitting power, but it needs to be reduced (and converted) prior to being applied to the traction motors. To make that happen, the ALP-45DP is carrying a power transformer along for the ride, and power transformers are heavy (particularly those for the 25hz frequency of the old PRR catenary). Typical third rail voltage does not have to be changed, so a transformer is not required for dual mode locomotive that get their electric power from a third rail.

I guess even a structural engineer remembers some the electrical stuff that rubbed off after 40 years of working with EE's..

[AlanB]

I guess even a structural engineer remembers some the electrical stuff that rubbed off after 40 years of working with EE's..

Thanks for confirming things!

[Aaron]

Here's a really stupid question: In small electronics, transformers have been giving way to switching power supplies for the last several years, with corresponding weight and size savings and reduced heat output. Is there any such possibility as a switching power supply for the colossal voltages we're talking about here that might someday be used instead of giant transformers on the locomotives? If not, why not? I'm sure there's some obvious answer I'm missing or unaware of, but I'm trying to expand my knowledge here.