Richmond, VA - Gimme the skinny....

[Joel N. Weber II]

Interesting point George. Is the track inside the tunnel on ballast or is it ballastless on the tunnel floor. If not the latter then there would possibly be 6+ inches to gain that way. Would be interesting to see what the study says about this matter. Afterall VRE also runs gallery cars on this route so sufficient clearance with electrification would be important. However, if you look at the situation in NYP, my suspicion is that they could do a 11kV electrification with as little as 1.5' clearance from train top to tunnel ceiling, perhaps a little less if ceiling rails are used with insulating sheets lining the ceiling.

Aside from the problem of modifying the locomotives, is there any reason not to consider 600-800 V catenary? That reduces the required air gap further; if you're approximately at the voltages the traction motors use anyway, the modifications to the locomotives shouldn't require much extra equipment; and the usual argument against such low voltages is that the substations etc become more expensive, but given a choice between expensive substations and expensive tunnel clearance work, the extra costs of the lower voltages may not be so bad.

 

[George Harris]

Tunnel south out of Washington Union Station. This tunnel just barely clears the Superliners as is without electrification. There is a street overpass shortly south of the south end, so lowering the track may not be an option. Don't know what they are going to do there. I would think a 2 to 3 feet must be found somewhere. This on e will be interesting. Also: 12th street overpass near L"Enfant Plaza only allowed something like 16'-6" clear when these tracks were electrified for the Pennsy freight trains. Do not know what they will do there. Even if CSX has no hope for Plate H, they would surely want to be able to pass the Plate F (17'-0") equipment that clearance that they have now permits.

Interesting point George. Is the track inside the tunnel on ballast or is it ballastless on the tunnel floor. If not the latter then there would possibly be 6+ inches to gain that way. Would be interesting to see what the study says about this matter. Afterall VRE also runs gallery cars on this route so sufficient clearance with electrification would be important. However, if you look at the situation in NYP, my suspicion is that they could do a 11kV electrification with as little as 1.5' clearance from train top to tunnel ceiling, perhaps a little less if ceiling rails are used with insulating sheets lining the ceiling.

I was last there for any length of time 30 years ago and last there at all 12 years ago. Unless it has changed, the track in the tunnel is ballasted, as is the track on the bridge in approach to the tunnel.

Just for information: The superliners are 16'-3" tall and the Chicago and west coast gallery cars are 15'-11" tall. Would assume that VRE's are the same,as I believe that they are Bombardier's standard design.

 

[KayBee]

Is that who owns the two big buildings in the block to the east of the station? If so, I'd think the taxpayers giving them a new building or two to replace the existing ones that happen to be in the way of where the tracks should go would be something that could be spun in a positive light of modernizing the museum or something. There are few museums that don't like getting new buildings. A parking garage could be thrown in to replace some of the lost space in the parking lots, too.

Actually, Broad Street Station IS the Science Museum. The buildings to the east are the main offices of the Va Department of Transportation.

Rafi, the American Orient Express used to park their train at the Science Museum for the Richmond segment of their "Antebellum South" trip. I wish those days would come again....sigh

 

[jis]

Aside from the problem of modifying the locomotives, is there any reason not to consider 600-800 V catenary? That reduces the required air gap further; if you're approximately at the voltages the traction motors use anyway, the modifications to the locomotives shouldn't require much extra equipment; and the usual argument against such low voltages is that the substations etc become more expensive, but given a choice between expensive substations and expensive tunnel clearance work, the extra costs of the lower voltages may not be so bad.

Collecting the necessary current at such low voltage will require several pantographs, which is not going to be easy to manage on an already crammed roof of an engine. Also, the motors these days are AC drive which requires variable frequency feed.So it is quite irrelevant what voltage the catenary is. Everything typically gets converted to 3kV or so DC which then feeds the drive alternators. So on the whole getting the voltage down substantially below 10kV will add considerable complication due to the heavy current that will need to be collected from the cat.

 

[PRR 60]

Aside from the problem of modifying the locomotives, is there any reason not to consider 600-800 V catenary? That reduces the required air gap further; if you're approximately at the voltages the traction motors use anyway, the modifications to the locomotives shouldn't require much extra equipment; and the usual argument against such low voltages is that the substations etc become more expensive, but given a choice between expensive substations and expensive tunnel clearance work, the extra costs of the lower voltages may not be so bad.

Collecting the necessary current at such low voltage will require several pantographs, which is not going to be easy to manage on an already crammed roof of an engine. Also, the motors these days are AC drive which requires variable frequency feed.So it is quite irrelevant what voltage the catenary is. Everything typically gets converted to 3kV or so DC which then feeds the drive alternators. So on the whole getting the voltage down substantially below 10kV will add considerable complication due to the heavy current that will need to be collected from the cat.

Not to mention that a typical catenary system itself does not have the current rating to power a train at 600v.

 

[AlanB]

Aside from the problem of modifying the locomotives, is there any reason not to consider 600-800 V catenary? That reduces the required air gap further; if you're approximately at the voltages the traction motors use anyway, the modifications to the locomotives shouldn't require much extra equipment; and the usual argument against such low voltages is that the substations etc become more expensive, but given a choice between expensive substations and expensive tunnel clearance work, the extra costs of the lower voltages may not be so bad.

Collecting the necessary current at such low voltage will require several pantographs, which is not going to be easy to manage on an already crammed roof of an engine. Also, the motors these days are AC drive which requires variable frequency feed.So it is quite irrelevant what voltage the catenary is. Everything typically gets converted to 3kV or so DC which then feeds the drive alternators. So on the whole getting the voltage down substantially below 10kV will add considerable complication due to the heavy current that will need to be collected from the cat.

Not to mention that a typical catenary system itself does not have the current rating to power a train at 600v.

Bill, would you be so kind as to please explain just what that means to those of us not in the power industry. :unsure:

 

[Joel N. Weber II]

Not to mention that a typical catenary system itself does not have the current rating to power a train at 600v.

What is atypical about the catenary the MBTA uses on part of the Blue Line, then? I'm pretty sure that's somewhere around 600V.

 

[Joel N. Weber II]

Not to mention that a typical catenary system itself does not have the current rating to power a train at 600v.

Bill, would you be so kind as to please explain just what that means to those of us not in the power industry. :unsure:

Wattage (ignoring power factor for AC) is proportional to voltage times current. (Current is measured in amps) If you want to apply some particular amount of force to the rails via the traction motors, it's going to require some particular wattage. So if you find the amount of current is too high, you can select a higher voltage to enable the use of a lower current, or vice versa. Higher voltages require thicker insulation; higher currents require thicker conductors. I think lower voltages also tend to lead to greater loss of power (measured in watts) per thousand feet of length of conductor than higher voltages.

 

[Ryan]

I think lower voltages also tend to lead to greater loss of power (measured in watts) per thousand feet of length of conductor than higher voltages.

Yes.

This is why power is transmitted over long distances by high voltage, high tension lines. Higher insulation isn't a problem because the cables are uninsulated, and the high voltage reduces the current loss and size of the conductor required.

 

[jis]

Not to mention that a typical catenary system itself does not have the current rating to power a train at 600v.

What is atypical about the catenary the MBTA uses on part of the Blue Line, then? I'm pretty sure that's somewhere around 600V.

I think there are a couple of things that makes it work. First those trains are very light and require relatively less power on the whole to operate. Second the collection of the power is distributed through the train thus reducing the need for high current density in the cat near a single pantograph.

Note that as far as cats or ceiling rails go these are not technically insurmountable problems since one could conceivably stick massive conductors and pantos to do the trick, but it does lead to significant inconveniences in the context of mainline high power non-distributed power operations.

 

[George Harris]

but with 200' it's probably possible to not demolish any buildings if a train heading south out of the platform track ends up pointed north on the mainline.
Whether 200' radius curves are a good idea is another question. I believe the California HSR documents claim there's European equipment designed for a minimum curve radius of 493'. But I'm not sure what the downsides would be of demanding that rolling stock be able to deal with 200' radius curves.

You are simply not going to run current railroad passenger equipment around a curve of 200 feet radius. Building a station approach that is not usable by the current Acela/Amfleet/Viewliner equipment is to put it as politely as possible, stupid.

For general reference: From the Manual of the American Railway Engineering and Maintenance of Way Associations (AREMA): "For curves above 13 degrees, the maximum coupler angle is exceeded. . . " 13 degrees is a radius of 441.68 feet.

Yes, there is freight equipment and smaller engines that can go around sharper curves.There have been and still are in some locations railroad branch lines with curves that have radii smaller than 440 feet, but in all cases there will be a set of restrictions on what can operate on these curves.

For curves that approach the 13 degree limit, speed is always limited to 10 mph or less to avoid wheel climb. Also, you will know every time a train goes around it as it will squeal LOUDLY. In new construction, curves of greater than 10 degrees are avoided if at all possible. (10 degrees = 573.69 feet) In industrial and yard trackage, curves of 12 degrees are usually permitted, but no more. (Radius = 478.34 feet)

The Calif HSR, due to one extreme case has a statement that the minimum radius curve will be 500 feet. Obviously, speed will be real slow on that radius of curve. the 493 feet minimum "for some European equipment" is 150 meters rounded up to the neares foot. Again, the train will be moving real slow at that speed. That number is based on the pragmatic reality that the European high speed equipment must be able to operate on tracks built on the original 18 whatever alignment in some places in their home countries.

 

[orulz]

Bringing this old thread back from the dead, the SEHSR has released their plans for the rail alignment between Richmond and Petersburg.

The plans call for a second track over both the James and the Appomattox Rivers, as well as double tracking and renovating the "S" line through Richmond, and triple tracking much of the "A" line.

For those of you who have been keeping track (anyone?) there was some question as to the routing the trains would take through Petersburg. Would they take the old ACL main through Colonial Heights to a station downtown, or stick to the CSX "A" line?

This chart seems to indicate they have decided to stick with the CSX "A" line. That's bad news for the town of Petersburg because their station will remain in a crappy part of town, but good news for SEHSR in general because the CSX alignment will be faster.

Regarding the new bridges (particularly the one over the Appomattox): I hope they do what they did with the new bridge at Possum Point: build the new bridge wide enough for two tracks, so if they ever need to triple track, all they'll need to do is put down rails. When you're talking about infrastructure like major railroad bridges that have a typical lifespan of 100 or 150 years, thinking along those lines is very appropriate.