MODERNIZING THE BONNER RAILWAGON.

Some creative types with Space X experience have been thinking about providing retail intermodal by putting containers on battery-powered bogies.  Union Pacific seem to be interested.

The concept under development by Parallel Systems would see intermodal containers carried by pairs of powered battery-electric wheelsets, moving in “platoons” of cars, but capable of splitting off to individual destinations en route. The company went public with its plan this week, saying it has raised $49.55 million for construction of the vehicles, as reported by CNBC, Fast Company, and other media outlets.

“We are interested in the Parallel System’s technology. We are familiar with it, and it is of interest. It’s of keen interest,” Union Pacific CEO Lance Fritz told investors and analysts on the railroad’s earnings call Thursday. “Candidly there are a lot of hurdles in front of that technology for deployment. Having said that, it could potentially be a game-changer if it proves out to be effective and workable. So I’d say keep your eye on it. We’re keeping our eye on it.”

The Parallel Systems proposal also merited interest from Ars Technica and the Institute of Electrical and Electronics Engineers, to a skeptical Instalanche.  The Ars Technica description provides the bridge between historical railroading and the proposed method of moving individual containers.

Parallel Systems isn’t just taking an existing freight train and swapping its diesel-electric locomotive for a battery version. Instead, it’s taking the traction motors and distributing them to every car on the train. It’s how many electric passenger trains operate, but it's a system that has been slow to migrate to the freight world.

Parallel Systems is going a step further, though. Each of its rail vehicles consists of a battery pack, electric motors, four wheels, and a package of sensors that allow it to operate autonomously. And since a large portion of the world’s freight is shipped via 20-foot containers, Parallel Systems is using the containers themselves to complete the car, bridging the gap between the sets of wheels at either end of a train car, also known as bogies.

Here’s how it works: two vehicles position themselves far enough apart to support the container, which is lowered by a crane. The vehicles then use their short- and long-range cameras to navigate the rails. Because each rail vehicle has everything it needs, it doesn’t have to be part of a long train. In theory, one container supported by two Parallel Systems vehicles could move from origin to destination by itself. In reality, though, they’ll likely end up traveling in platoons. (Parallel Systems doesn’t call them trains because the individual cars aren’t coupled.)

The Institute's writeup explains how platooning by these latter-day merchandise despatch cars differs from the drafting behavior of truckers.

In a traditional platoon, efficiency is unequal since the leader takes the brunt of the aerodynamic forces to make things easier on all of the following vehicles, and obviously rotating leaders won’t work on rail. But Parallel Systems’ vehicles can go bumper to bumper and push each other, meaning that overall energy use can be equalized. Neat!

I made that interurban reference for a reason, dear reader.  The North Shore Line's Electroliner had the seating capacity of three heavy interurban cars, but because it was lighter, it had only eight of its ten axles powered.  There are some constraints of traditional motor control circuitry that contributed to providing them in groups of four.  A train of three powered heavy interurban cars had twelve axles powered, and it had a higher balancing speed than the Electroliner.  Why?  The lead car split the wind, and the additional motors on the following two cars had more oomph to overcome the wind resistance compared to the Electroliner.  But adding a fourth car didn't add more speed, as the current draw of four more motors on a trolley wire of fixed capacity worked against them.  The Parallel Systems people are aware of that problem.

“We think our platoon sizes are ideally between ten and 50 cars,” Matt Soule, CEO of Parallel Systems, told Ars. “With ten, you’re sharing the aerodynamic load over multiple cars, and the benefits of that kind of asymptote out around ten cars. But on the business case side, in terms of serving the volumes that might be there, we think moving in platoons of up to 50 is the max.”

"Asymptote out" is that balance speed phenomenon.  But if your platoon is fifty platforms, aren't you really in the realm of a train, as commenters on all the posts have noted.

We have only begun, dear reader, to make interurban references.  If you've stayed with me this far, you might wonder why containers on the public highways are on full trailers tied to the tractor, rather than there being a pickup truck configured to carry the front end, and a roller skate configured to carry the rear.  The answer: a container isn't robust enough to handle the kind of twisting around that such a rig would encounter, whether on the highway, or on these Parallel Systems skates.  Alan "Armchair Urbanist" Fisher raises that and a number of other points, splicing all sorts of reality checks into Parallel's video.

If that rigid frame under the container is required to keep it from flexing, perhaps you're getting closer to Train World, specifically to the Bonner Railwagon.  Sometimes the oddest things stick with you, such as a reference to interurban piggyback in the June, 1960 Trains.

If you don't have wheel assemblies on the containers, you don't have to use inboard bearing bogies on the platform, and contemporary lifting cranes place the containers on the platform, rather than relying on a teamster to set the trailer back onto the ramp and then pulling the beam forward to get the next trailer on.

I pause for a moment for the obligatory Cold Spring Shops reference.  That "primeval end-loading" was the sliding of small containers through the end door of an enclosed car.

If we consider running powered dollies in trains, we might have the advantage of being able to use smaller batteries.  I'm not persuaded that Parallel's dollies have this eight hundred kilometer (500 mile) range anyway.  But if you're hauling them at the end of an intermodal train with diesels distributed throughout that train, you don't require that sort of range.  On the other hand, you have to peddle those cars to those trackside consignees.

Again, the interurbans were working on that long ago.  Because the steam railroads wouldn't interchange with them anyway, the interurbans and rapid transit companies invented all sorts of couplers that made the electrical and brake connections at the same time they joined the cars.  The Germans have been working on improving those couplers and adapting them to freight cars.  At the moment, their focus is on being able to assemble cars into trains more quickly, without all the connecting of links and airhoses that the European hook couplers involve.  But if you can write an algorithm to couple the cars, can it be that hard to write an algorithm to uncouple them?  "With fully-automatic couplers that make or unmake brake and communication line connections concurrently with the addition or deletion of cars, wouldn't the simpler solution be to do adds and drops on the fly? On the other hand, particularly with rapid-transit equipment, a drop or add can be made in a stop of about a minute."  That is, we run the intermodal train in the fashion of the British railways that "slipped" coaches off the hind end of their express trains, in order to provide country-bound Londoners access to towns such as Reading or Westbury whilst not stopping short of Exeter or Plymouth.

Then there's the challenge of getting the retail container to the consignee's siding.  Michigan State's Nick Little explains that to the Institute.

In theory, you could make these vehicles a lot more responsive by being able to send a signal to some...trackside device that would change a switch for dynamic rerouting, but this isn’t something that currently exists across freight-rail networks. It does exist on tramways; urban streetcars work that way. Could it be done? Heck, yes. The technology is there.

Indeed it is, and many model railroaders have learned how to use their command control throttle to line switches.  Put it together, and you have a retail intermodal delivery method that's compatible with linehaul railroading: equip the platforms, and some or all of the linehaul cars with fully automatic couplers, marshal the platforms at the rear of a through train in such a way as to slip the cuts of containers first off at the hind end, use the information technology to perform the slip in such a way that the through train can get far enough ahead of the platforms going to battery power before that switch has to be thrown, and control the speed of the motorized platforms to make a safe stop at the consignee's dock.