This is well out of date (2009), electronically controlled brakes have already proven their worth, at least for our customers [1]. For example one of our customers, Rio Tinto in Western Australia, deployed ECP which allowed them to reduce headway [2]. Along with driverless trains, operations optimisation software and other innovations allows them run more trains and get more iron ore to port with the same infrastructure.

[1] I am CTO of a railroad operations software startup http://biarrirail.com/

[2] https://en.wikipedia.org/wiki/Headway

So what's the failure risk of the new model vs the old model? It seems like the old thing used straightforward physics and mechanics. Whereas the new thing is more complex both in implementation and types of things it relies on. I'm sure they might have insurance that negates this consideration but I still consider human life. ;)

Note: It might also be worth considering how many of the braking events are safety-critical.

Agreed, however I have not seen any specifics on that, the headway changes had a direct effect on our software, reliability and maintenance aren't factors for us.

Rio Tinto are extremely safety conscious, for example they drug and alcohol test everyone, regardless of role even vendors. They're also operating in the Pilbara region an incredibly harsh desert environment in Western Australia. So I would guess that they wouldn't accept an increase in safety risks and the trade off between risk of break downs, maintenance cost and the throughput of their rail network is positive.

Why not regenerative braking?

Also generating eddy currents against the rails would be a cool way to slow down without wearing down brake pads.

There is nowhere to regenerate the energy to (no battery, and no overhead line to feed the energy to where it can power other trains).

Instead, diesel-electric locomotives have dynamic braking. The motors are reconnected as generators as is the case with regenerative braking, but the electrical energy is fed into what is basically giant heatsink (fan-cooled resistor grids).

As for eddy currents, I imagine there would not be enough interface area between the rail and the electromagnetic element to produce enough braking force against the huge amount of kinetic energy a heavy moving train has. Dynamic braking already solves the problem of saving wear from friction braking, consider it similar to engine braking a car.

Eddy current brakes actually exist: https://en.wikipedia.org/wiki/Eddy_current_brake

This sounds like what causes magnets to fall more slowly inside a copper tube. But applied to train rails.

That raises an interesting question about the life of rail car brakes.

The cost of constant attention seems like it would be significant. I wonder how the brakes are constructed to minimize maintenance costs.

The article does mention adding other sensor data to the ECP bus, brake life could be monitored in real time.

From what I was able to find, brakes last between 240,000km - 2.5million km, depending on the material used in the pads. I would also guess that terrain and weight play a big factor.

source: http://www.railjournal.com/index.php/rolling-stock/a-life-cy...

That is right. IoT technolgy is a big deal in the rail market, for example GE's Evolution locos produce 150,000 data points per minute. This can feed real-time analytics as well as predictive maintenance requirements, which the company I work for deals with.

This is actually really interesting. How granular are these metrics? Do individual bearings have sensors on them for example? Does the locomotive cut a maintenance ticket when light bulbs burn out? How many different sensors contribute to the 150,000 data points?

The statistic comes from this article: http://www.cnet.com/news/at-ge-making-the-most-advanced-loco...

I think railroad brake shoes are usually cast iron.