Railroad Catenary Wire Construction Cost

I read somewhere ( railway construction costs in the early 20th century), that catenary would double the cost of a rail line. I don't think this took into account the cost of power substations and the rebuilding of overpasses and tunnels where required. Any information I had on the subject was based on old electrification projects in the early years of electrification and wouldn't be pertinent in today's economy. A completely brand new line would probably cost less to build than a retrofit line where infrastructure would play a larger role.

This really is a narrow field of construction process. I'm sure many unspecified parameters could radically change your cost estimates. Here are a few examples that will radically change any cost estimates:

• Right of way costs
• Existing catenary train run or new line
• Terrain difficulties for catenary architecture supports
• Swamps
• Rivers
• Gorges
• Tunnel
• Desert
• Weather conditions
• Union wages

With all of these unspecified variables, all that you can do is guess.

You might consider checking the news links for a catenary repair cost done recently. To attempt to scale that cost to your new line I'd break the total repair costs into two numbers that add up to the total cost reported in the story. The first would be a fixed charge for doing repairs and the second would be a charge for the installation of that length of wire. That latter number can then be the mileage basis for a charge, along with your own single time guestimate set up charge.

But without working in the business, or knowing where this line will be I'd say $500,000 is a reasonable guess.

Not my field, but I doubt that $500,000 would get you more than half a mile of catenary.

Agreed, $500,000 will likely be greatly less than actually needed if no infrastructure already exists. But for a theoretical school assignment, any value will be just as useful as any other. So by producing both a basis for coming up with the capricious number and by pointing out what assumptions have been made, the student has shown a clear thought process. Isn't that what the teacher is looking for?

This is for a project my engineering class is working on. It is more than just showing the process, I will be competing against other colleges and want to get it as right as I can. I found a Civil Engineer's thesis from 2006 on the same subject, but instead of designing a catenary wire, he wanted to use about a dozen $200'000 pieces of equipment instead.

Send me a PM and I will give you more info on the project.

Drew

Sorry, but while I do work in a high energy field of electronics, I do not work in this field. All I can do for you, beyond what I've already proposed, is tell you to break this up into smaller subsections that task members can focus on. Arrange for at least weekly meetings where task members relay their progress.

You've already found a thesis that proposed building a similar system. So you're well ahead of me.

Good Luck

Perhaps you could help me with another aspect. I have read about home electricity generating systems that can be fed back into the grid when there is a surplus of electricity. What happens to the grid when this occurs? How much electricity can be put onto the grid (given sufficient wiring means) before it affects the power plant? Will the power plant shrug it off by powering down the load on its generators?

If I am imposing, or asking something that will take up too much time, don't worry. I was planning on posting this as its own question anyway.

I plan on working in Mechanical Engineering, but am only a sophomore now. So I do not know alot yet. I do have 12 years experience in pipeline fuel, storage and issue equipment from the Air Force and a cross country pipeline company though.

Drew

There really isn't a simple answer here. First, not every utility in the United States has to credit domestically generated power that has been dumped back into the grid. Those that do, have power meters that actually run backwards when the small provider powers the grid. (I believe that all power meters will do this but just in case some don't...) Now the only time that the utility may question the configuration will be the rare time that a small provider provided more power during the billing cycle than what was consumed from the grid during the same time, making a net profit for the small provider. Most utilities that have to credit power returned to the grid instead of billing solely for power consumed were granted adding a fixed fee for basically maintaining the power lines themselves. I've never heard of anybody but some farmers with wind turbines making an occasional profit from this arrangement but in theory it can happen. I take that back, I know of a former watermill powered factory converted to a condominium in Massachusetts that installed a small hydro-generator. The maintenance of this system ended up overwhelming the condominium board and entropy ultimately did its thing.

But to be more on point of your question, the small provider just ends up reducing the total load the large power plants need to drive the grid. This will not dramatically affect the grid itself. Of course this can be taken to absurd values that will make a problem. But this will require becoming your own large megawatt power producer.

Just to include the obvious, the power you produce must be compatible to the grid. It must be in the correct voltages and currents and these must be properly phased to the grid to not cause a problem. This is not difficult to do correctly but it's also not difficult to do it wrong.

Not sure if the units are exactly correct, but how about 900 kWh? I do not know about phase, voltage or frequency.

Drew

That's not an insignificant amount of energy. (Gotta watch those double negatives.) I mean that's a lot of energy.

As I mentioned in my earlier post, dumping power back onto the grid of a megawatt would likely give power production facilities trouble. The number and unit you choose would mean you'd be doing this continuously for nearly an hour. So if you expect this much regenerative braking to dump power back into the grid some careful considerations should be done.

According to a thesis paper I found, that is how much energy an average train crossing Cajon pass in California can generate through dynamic braking. I don't know if I am ready to tackle the voltage and phase dilemma, right now we are just doing a proof of concept model using toy trains. I did want to include data on how much it would cost to string up catenary wires though. The original thesis used a battery car coupled to the locomotives, he spoke of using a flywheel for a battery. Unfortunately it would require stopping the train to hook up and unhook the car. I thought it would be better to just connect the locomotives to the grid in areas where trains use dynamic braking because the author wrote of losses up to 70% transferring the energy through the flywheel.

Drew

Hmmm, I suspect that the thesis is anticipating all of the mechanically stored energy from the whole elevation drop for that number. All of that energy will not need to be absorbed at once at the bottom of the run. By using a catenary system you will not have to bring a flywheel or battery out to the locomotive, you'll have the catenary connection for that. Also there's nothing that says that you have dump all of this power back into the grid. You could just temporarily store this in the battery/flywheel that's part of your catenary power distribution system.

From the thesis, it looks like there is a great loss (about 70% using a flywheel). That is why I thought of using the catenary. I think you are right, that was a total accumulation of the downhill run.

Here is a sample of the data from the thesis:

Locomotives (8) Cars (76) Weight (7176) (tons) Energy 2744 (kWh) Time 4:39(h:m)

This was the highest value listed.

I really got so much to learn...I think I will be better after Physics, but thermodynamics will be the real eye opener. I hate getting ahead of myself, this all started as a small project for a local engineering student competition (with the winner going on to statewide finals). I know that I am not ready to do a thesis on this, but it is quickly turning into a project of that depth. My original project was just a proof of concept, make a model train show dynamic braking. Perhaps I should cut it at that and save this for a thesis in a few years. The problem I have is i feel like I am cheating myself if I only re-do what is already proven...but I know I am only a sophomore and not ready for thesis level work.

Drew

You'll do just fine.

As far as doing really new work, few people ever knowingly do really new work. Most of the time really new work happens because you've pushed the envelope at a point that nobody thought of before.

Good Luck

Thanks.

I think I will just do the proof of concept work, my model will use a toy train that uses the rails to power the engines kinda like a catenary rail system. If I can show that the system generates on the downhill slope, it will be enough to show that the same would happen on a larger scale with real locomotives. I will allow for further research and hint at a thesis on the topic at a later date.

Drew

The major problem that utilities face with importing excess power from independent AC power generators is synchronization and maintaining system stability. Although reactive power is not real power, it must be supplied by generators in order to maintain voltage, frequency, power factor, and stability within defined limits. Means reactive power must be supplied but for which no revenue is directly received. DC converters at grid interties can be used to avoid some of those problems.

One proposal floating around is the use of large numbers of plug in electric cars to provide emergency power to the distribution utility by backfeeding through the charging circuit. That could actually be done fairly easily but it seems to me to be a real stretch trying to take that concept beyond the sectionalized distribution level.

That is what I was afraid of. I am still hoping someone will give an estimate cost per mile so I don't have to estimate it by guessing.

Drew

How about contacting a railroad company's engineering section. They would be in the best position to advise you on cost.

In the U.S., about $1,000,000.00 per mile not including substations (and that's based on a current 35 mile long upgrade project that is under construction). If substations and associated equipment are included; $1.5 - $2M per mile.

Most electrification projects are undertaken by state owned railways. As such the cost of the project will be in the public domain. A little research should be able to turn up the project costs. Failing that read a serious railway journal, such as Modern Railways in the UK, which goes into some depth on infrastructure projects.

When looking at costs remember that that x route miles may translate to 3 or 4x track miles once double track, stations and sidings are taken into account.