I wouldn’t do that. 
I’m just spit balling numbers based on a few publicly available resources. There could and probably are issues in the numbers I got. One takeaway is that there can be significant variations for types of freight. But the basic Newtonian physics does a pretty good job.
I would have guessed 1 or 2 semis per rail car, since a rail car holds 2 containers and a semi hauls 1 or (with second trailer) 2 containers.
I wonder if it would be more efficient to treat a loco battery as a container, and instead of unhitching and switching loco’s, swap containers; they pull into a yard where a crane lifts a battery off the “coal tender” car and dumps on a new one.
Well, my Tesla Model 3 weighs 2 tons (4100lb) so assuming it’s half battery, a ton of battery - and about 10’ x 5’ x (a few inches) for the battery pack of about 75kWh. For something like a loco, about 86 Model 3’s worth of batteries is not a lot for an industrial hauler. The semi is allegedly 900kWh, or about 12 Model 3’s.
Have not read all the posts, so apologies if this is repetitious, but in the early days of automobiles, people would buy or even build their own cars long before gas stations appeared. Infrastructure followed rapidly.
The labels I read as I sit waiting are in the 190,000# to 230,000# range per rail car. The flatbeds you see carrying 2 semi trailers have a lot of empty space compared to a densely packed rail car.
Intermodal rail cars that fit two shipping containers stacked on top of each other are a bit shorter than standard rail cars. Intermodal cars have container wells that are 40’, 48’, or 53’ long. A typical covered hopper car is more like 60’ (and wider than a shipping container, too), and flat deck cars can range up to 90’
Problem solved! “The US Department of Transportation have authorized a $250M grant program to fund Wireless EV charging roads.” EEVblog (30 min)
https://www.youtube.com/watch?v=sisD61ohzK0
I hope you’re being tongue in cheek. $250M is barely enough to study the citing problem, much less implement anything.
Why not just put a battery pack and drive bogey on each car? The locomotive would become a small car for the engineer to eat lunch in and control the train.
Pairs really well with Solar Roads
I haven’t watched the YouTube video (which has a title " Wireless Freakin’ EV Charging Roads! A $250M Boondoggle", so you know it’s unbiased and objective), because videos are a terrible way to convey detailed facts.
I did track down the program though. It is a specific funding from congress, sponsored by a Representative from Michigan ( Rep. Stevens Introduces Bill to Expand Wireless EV Charging Programs at the Federal Level | Congresswoman Haley Stevens (house.gov)).
It is apparently an expansion on a 2022 Michigan program to create a length of public road with wireless charging capability. ( Gov. Whitmer Announces First-in-the-U.S. Wireless Electric Vehicle Charging Road System Contract Awarded by MDOT (michigan.gov))
It seems that with the amount of vehicle development and testing in Michigan, the state decided to provide some public roads for automotive manufacturers to test wireless charging of vehicles being developed. The first (modest- quarter mile) stretch of such roadway was unveiled recently ( Detroit boasts wireless charging road project for electric vehicles (freep.com)), created with about $2M of state funds and $4M of private funds.
So, my assessment is that this (relatively) small portion of the overall infrastructure funding was prompted out of Congress and is set up to allow DoT to fund small scale pilot demonstrations to test out the practicality of wireless charging through public roadways. Unless they start handing the funding out to entities with no wireless charging or EV capability, it’s not a “boondoggle”.
Good to know. Thanks for taking the time to research and to report back.
My point was not that it was a boondoggle. I was wondering what sentiment this tidbit represented:
Specifically his “Problem solved!” intro.
My comment was intended only to speak to the scale of the grant versus the scale of dollars needed to install EV charging all around the US interstate network, and eventually the entire rest of the US road network such that EV charging was as ubiquitous (relative to need) as are gas stations today.
I was being a bit snarky because it is a boondoggle. I know it’s a long video but the main point is, it’s a good idea being applied in the wrong application. You don’t put it in normal roads because it’s too complicated (that’s covered in the first 5 minutes). It belongs in airports or parking garages.
Any wireless charging of electric vehicles seems to my non-electrical-engineer mind to be highly ineffcient. When I slow charge I’m pumping 26A 240V through a wire into my car. I have trouble imagining the coils that would handle that with an appreciable air gap. (Not to mention the issues if there’s an accident on the live charging road.)
I think it is the opposite. Efficiency of wireless chargers is low enough that anywhere a vehicle is stopped, it will be better to use a cable. For vehicles, wireless charging only makes sense in places where a cable is impossible, like on the road. Wireless charging of phones is only tolerable because the amount of power wasted is low enough to not matter, but dropping from 95% to 50% efficiency charging a parked car would represent a huge waste.
It is possible wireless roads will never be a useful technology, but we won’t know that unless research is done. Perhaps the $250 million could be better spent on different research, but it is also very reasonable to research many things at the same time (for example, wireless charging, new battery chemistry, more efficient tire compounds, etc.). Research with a high risk of failure is also a reasonable thing to do. There is a big difference between “unlikely to be successful, but a huge win if we can get it to work” and “impossible to be successful, a waste of money from the start.” There is also a difference between “I, a non-expert, don’t know how this can be done” and “actually impossible.”
Perhaps you place a wireless charger at every bus stop along a bus route, so that every time the bus stops for passengers, it gets a small amount of recharge?
One of the advantages of stop and go traffic in an electric car is that the car brakes by regen, recouping some of the energy of motion. In stop-and-go, it is not “idling” and burning excessive amounts of fuel simply to keep the engine turning. I imagine any EV bus would certainly be taking advantage of this option.
I had a hybrid Camry - it got highway mileage in the city because unless you pushed really hard on the brake, it slowed by regen. It used electric power to assist acceleration, limiting that burst of fuel. It, like my gas-powered BMW does, would stop the engine when stopped in traffic or at lights. (But if the cabin temperature got too high/low, they would kick in the engine to power the AC or make more heat.)
I have trouble imagining how a “charging highway” would work, particularly in northern North America where winter takes a heaving toll on simple paving. As I said earlier, the current demand to re-charge is very high. However, yes, spending $250M to figure out just how and in what circumstances it might work is a worthwhile thing.
(I note that Apple spent a few years and even announced a product that was essentially a small mat where you could simply toss your phone and watch etc on randomly and they charged - and gave up because it could not work with overlapping charge coils. IIRC there was a heat problem.)
Something like that does make sense, but has to be weighed against the cost of putting enough batteries on the bus to complete an entire day’s route without recharging. The fleet owner of transit busses (and delivery vehicles) should have a very good idea of how many miles are actually driven daily, and so should be able to buy vehicles with appropriate ranges.
A very brief search says that the average transit bus drives about 44,000 miles per year, which is about 140 or 120 miles per day, depending on a 6 or 7 day schedule. A transit fleet could probably consist of some number of 100 mile and 200 mile range busses, and would just need to allocate the correct bus to the correct route. This already happens with different size busses to different routes.
I’m not sure charging for a minute or two at a street stop will help, but it might be worth charging for longer stops at hubs, but for longer stops it also might not be a problem to have the driver or robot connect a charging cable.
I suppose the point of wireless charging along a road is that all you have to replace is the actual consumption. Ideally all of it but maybe only half of it.
To make the math simple, assume 60mph = 1 mile per minute. If you can charge as much in a minute despite the air gap as the car consumes in a minute over that mile, you now have a car that’s fully powered by the road and the car will have infinite range as long as it remains on a charging road. If the road can only replace half the energy the car consumes in that mile and minute, then the car’s range is doubled. If it can travel 300 miles = 5 hours on a unpowered road it could now travel 600 miles = 10 hours on a powered road.
The powered road is a range extender. Which results in less (probably not no) need to charge at rest stops or at overnights.
How the math all works out is beyond my expertise. But the idea isn’t obviously wacky.
Wireless charging is fairly efficient so long as the size of the antenna is much larger than the width of the gap. If you fill the entire bottom of the car with an antenna (and there’s no reason you wouldn’t), that’s an order of magnitude or so more than the gap between antenna and road. Of course, if you have a nice, flat, smooth road, you can suspend the antenna even lower.
All that said, if you want to provide power via the roads, it’s probably a lot easier to do it with overhead wires and contact bars. It’d be more complicated for cars than it is for trains, because trains can use the metal rails to complete the circuit and rubber-tired cars can’t do that, but you could probably still come up with something better than induction chargers.
Overhead wires would have to be placed higher than the tallest possible vehicle that could drive there, which is going to be… quite tall.
Not that I think induction chargers have any hope of becoming commonplace, but they’re at least fully compatible with normal roads and don’t require fiddly mechanical bits on the cars. Any charging inefficiency is massively outweighed by those factors.