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Trains are more efficient and less polluting than other transportation modes

citylab.com

321–330 of 334 posts

Re: Trains are more efficient and less polluting than other transportation modes

#321

Earlier quoted context omitted.

210kwh for 3575 lbs comes from the tesla powepack specs: https://www.tesla.com/powerpack Furthermore, it makes zero sense to compare "3000kw x 4 hours" since diesel electric locomotives can run for N>>>4 hours. Furthermore, you're comparing the weight of batteries alone compared to the weight of a whole locomotive.

> Furthermore, it makes zero sense to compare "3000kw x 4 hours" since diesel electric locomotives can run for N>>>4 hours. This is simply you reframing the conversation from using batteries to allow hybrid electric trains to use short sections of non-electrified tracks to hybrid electric trains won't work because they don't have the range of a diesel locomotive. I'm going to put this down as you're unwilling to argu…

You're not comparing hybrid against diesel-electric, you're comparing hybrid against fully electric. The cost of putting batteries in your rolling stock might or might not be higher than electrifying the last 5%. Either way, it's small compared to the cost of electrifying the 95%.

Note that the eastern seaboard (with its bridges and tunnels and topography) is getting electrified; the long and flat midwest is not.

Re: Trains are more efficient and less polluting than other transportation modes

#323

Earlier quoted context omitted.

Sounds like you're referring to the University of Baltimore/MICA light rail stop[0], where you have to get off if heading south or heading north but not on the Penn line, to catch the ' Penn Station - Camden Yards' line. I mean, it's in the name of the light rail line...it lets you off right at the station[1]. [0] https://www.google.com/maps/place/University+of+Baltimore+-+... [1] https://www.google.com/maps/place/Pe…

Oh, my bad. I don't know how I managed to live a year in the city and not know about the second line. I've only ridden the BWI/Hunt Valley trains.

The real criticism of the light rail is that there's really _only_ one line, north to south. And the (part subway) metro train serves a similar route, NW to east side of downtown.[0]

99% of all the light rail "lines" ride the same track. The Penn-Camden "line" veers off the main tracks right at that Mt Royal stop (MICA/UB), and only goes to Penn, then back to the main line at Mt Royal, then headed to Camden Yards. It's probably the least common "line" to see.

[0] http://www.urbanrail.net/am/balt/baltimore.htm

Re: Trains are more efficient and less polluting than other transportation modes

#324
post #207

Earlier quoted context omitted.

For comparison, in the UK there are around 8 trains per hour during peak times between London and Cambridge (around twice the distance of DC-Baltimore). I'd imagine there are cities that have even more per hour in central Europe.

Although according to Google Washington DC has 700,000 people and Baltimore 600,000. Probably a more realistic comparison would be Bristol and Southampton/Portsmouth where there is realistically 1 train an hour (technically 2, but the second one has a change and runs 8 minutes after the first one). Comparing trains from London is not really fair because virtually every train in the south ends up in London eventually.…

that's a story and a half you could tell. No buses? And I wonder why blablacar hasn't taken off in the UK

Re: Trains are more efficient and less polluting than other transportation modes

#325
post #307

Earlier quoted context omitted.

Fast yes, cheap not at all. Conventional (not high speed) trains in Spain are cheap, but there are fewer and fewer of those. If you want to travel cheaply you mostly have to take a bus. Most trains here are now only for the rich.

I guess your definition for "the rich" is "not poor": 57€ for a 700 km travel is cheap compared to a car that will take x2 the time, unless you are OK with burning double the money on fuel and ignoring speed limits, of course risking fines and license suspension. A full car will be cheaper if you ignore the cost of the car itself + maintenance and saved time. Families use to travel by car on holidays only because the…

I am comparing high speed rail to conventional rail. High speed tickets are at least twice as much. The price of a bus is similar to the conventional train which is disappearing leaving the bus as the only cheap alternative. You are probably not poor.

Re: Trains are more efficient and less polluting than other transportation modes

#326
post #320

Earlier quoted context omitted.

I don't know where you're getting your information, but US real estate rents and prices are low by developed economy standards. Here is a link: http://www.newgeography.com/content/006201-15th-annual-demog... "The most affordable major housing markets are in the United States, with a moderately unaffordable Median Multiple of 3.9, followed by Canada (4.3) and Singapore (4.6). Ireland and the United Kingdom both have M…

This study is focused on price to buy, where a huge segment of the population are renters. This is the core issue with so many of these reports. Focusing on buying already rules out a huge segment of the population (incidentally the ones who have trouble surviving!), and ignores the fact that rent/buy ratios are very different between markets. US buying prices are relatively low because of how the entire economy is b…

There is a connection between prices and rents that can be warped temporarily and be permanently different in certain locales. However if you look at the table in the link below, the price-to-rent ratio clusters around the median for most places.

In the US currently it's slightly more favorable to be a renter than a buyer compared to the historical price-to-rent ratio. If anything most of the deviations from the norm are towards making buying more expensive than renting.

https://smartasset.com/mortgage/price-to-rent-ratio-in-us-ci...

Re: Trains are more efficient and less polluting than other transportation modes

#327

The main reason US cities rely on automobiles is because the "job watershed" of a private automobile exceeds the job watershed of train systems everywhere in the US, even New York City. The job watershed is the number of jobs within commuting distance, whatever your tolerance for a commute is, given a transportation modality. In some cities the automobile job watershed is 100x larger than the transit job watershed. T…

The problem with buses is that they're typically slow compared to even subway/metro rail (let alone inter-city). That doesn't mean they're not the right fit in a wide variety of scenarios (for example, they're about perfect for small/medium cities that can't afford to invest a whole lot in intra-city rail, and they're the only viable option for smaller cities/towns that aren't already stops on a larger inter-city rai…

Bus rapid transit (BRT) refers to reserving lanes along existing roads strictly for buses, and doing so along stretches with few controlled intersections, or even changing the timing on stoplights to ease the flow of the BRT vehicles. BRT is much faster than traditional bus mass transit.

Re: Trains are more efficient and less polluting than other transportation modes

#329

Earlier quoted context omitted.

You, strangely, ignored the parent's point that you would just be using the batteries to reduce the amount of overhead wires you need, i.e. one would have opportunity to recharge several times a day. (It's not helpful to focus on the specifics of a proof of concept--unimportant in this discussion about what is feasible--versus the fundamental figures of merit of the technology... Unless one is prepared to make the ca…

I don't think you've run the numbers. A tesla powerpack is 50kw, 210kwh, and weighs 3500lbs. A freight train that would normally be pulled by four 3,000kw diesel electric locomotives would need 240 powerpacks, and could run for four hours before needing a full recharge. Those powerpacks would weigh 420 tons - the equivalent of say, four fully loaded freight cars, and cost around $25M (plus whatever the locomotives co…

You just did it again. Used specifics from one application to pessimistically (and wrongly) apply to the technology generally. Also, you keep assuming the 4 3000kW locomotives will be running flat out, which is a terrible assumption (and would cause a conventional locomotive to quickly deplete its fuel, if not destroy its engine).

Here, I'll do it for you. Good Panasonic cells get about 250Wh/kg, or 0.9MJ/kg. Assume an electric-optimized locomotive would be able to achieve about half its weight in cells, with a useful energy density of 0.45MJ/kg. Assume about 1 locomotive for every 9 cars, and with each car weighing the same as each locomotive. So the whole train's effective energy density is 0.045MJ/kg.

The "rolling resistance" of a typical train is about 0.002, conservatively. That is a weight of 1 kgf has a resistance of 0.002kgf. (EDIT: This is a good assumption that works up to 60mph, the speed limit of freight trains, but at the typical low average speed of freight trains, it's actually about half that value: https://slideplayer.com/slide/4696076/15/images/12/Freight+T... )

The range is thus just: (specific energy)/((rolling resistance) * gravity) or: 0.045MJ/kg/(.002 * 9.8m/s^2) = ~2300km. https://www.google.com/search?q=0.045MJ%2Fkg%2F.002/(9.8m%2F...

That's enough to go from the center of the continental US to the coast on a single charge. (and from what I understand, 1 engine for every 9 cars is not uncommon)

If we have one engine for every 4 cars, you can now cross the continental US on a single charge. But remember, the discussion was about multiple recharges per trip, so there's WAY more battery here than you actually need.

And to just give an idea of the power available, 130 tons is a typical car laden weight. 65 tons of Panasonic cells gives you 16.25MWh of storage. Cells like that can discharge their cells about 12 minutes. Lets make it 30 minutes, conservatively. That gives a power at the cell level of 32500 kilowatts, ten times your 3000kW locomotive. Batteries are plenty powerful.

(And the cost is offset easily in fuel costs, as long as the battery is given the usage of about one full cycle at least once a week.)

You might point out energy requirements for braking and climbing hills. But remember that one of the greatest advantages of battery-electrics is regenerative braking. Most of the energy consumed in increasing elevation can be recovered on the way back down.

(As far as costs go, the battery pack should--including the price of industrial electricity and typical costs for automotive batteries at scale--pay for itself in fuel cost savings in about 500 cycle-equivalents while the cells should last at least 1000... meaning the overall added cost is potentially negative... meaning it's a market opportunity.)

Re: Trains are more efficient and less polluting than other transportation modes

#330

Earlier quoted context omitted.

Yes, such as roads, which can be replaced or built over with rail almost always. (Including light rail like trams.) The problem shared between both is lack of walkability. Not insoluble but requires more tunnels or overpasses.

It's a lot safer to walk over train tracks than to walk across a road. Where walkability is a concern, light rail is an option. I'm moving from NYC to Denver, and their new light rail system seems like such an upgrade from the car-congested streets above a sweaty slow subway.

Don't do this in London or much of south east England, stepping on the electrified third rail will probably kill you.
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