Mid Train Helpers

Linked by radio.

Usually known as "Distributed power"

Engineer can have the units operate in lockstep with the head end, or control the set independently.

---PCJ

Ralph M posted:

How does the mid-train helper thing work? Are they crewed or somehow MU'd to the head end  units?

 

Depends on the era you are inquiring about, i.e. steam, early diesels, or today's modern computer controlled high HP diesels.

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Here's how the Western Maryland was doing it in April, 1975.The mid-train helpers of this westbound coal drag are approaching the east portal of Savage Tunnel. This train's passing concluded a weekend campout here for myself and 5 of my high-school buddies from nearby Frostburg,MD. Camping at trackside locations would be a regular summer activity for the next 10 years.

This part of the WM Connellsville Sub would go silent in another year, today hikers/bikers enjoy this great view on the GAP trail, but I would love a time machine to take me and my Nikons back to 1975 and re-photograph all I missed then... 

Kodak 126 photo by Warren W. Jenkins

It's interesting to view the end of the car ahead of the engine when working on a mid-train or rear-end helper.  There is not much to distract you from paying close attention to the brake pipe gauge.  I will guarantee that I always paid close attention to the wheels on the train ahead of the helper, any time a curve made them visible.  And, of course the train behind the helper was visible in the side mirror.

One thing guaranteed to cause tension is being on a mid-train helper when the brakes go to Emergency from any intentional or unintentional cause.  At the least, there is probably some slack action coming, and, at the worst, there might also be a derailment (and the helper might end up as part of it).

Under curiosity, was this ever attempted with steam? I'm familiar with the pushers at the end of a consist, but did they ever get inserted in the middle? The article our esteemed webmaster linked to would seem to rule out an automated mechanism...

RootBeerRail posted:

Under curiosity, was this ever attempted with steam?

Absolutely yes. One of the more famous applications of multiple steam locomotive usage was the Western Maryland, who used two 2-8-os on the point, two more 2-8-0s mid train, and two more 2-8-0s pushing on the rear. For big time mountain railroading, the Southern Pacific with their massive cab forward 4-8-8-2 articulated locomotives on Donner Pass (one on the point, one in the mid-train position, and another pushing on the rear.

I'm familiar with the pushers at the end of a consist, but did they ever get inserted in the middle? The article our esteemed webmaster linked to would seem to rule out an automated mechanism...

SP used to have formuls for placing diesel helpers on trains in the back of employee timetables.

In steam days, both Santa Fe and Union Pacific used mid-train helpers on Cajon Pass.  The usual configuration was two non-articulated or one (U.P.) articulated steam engines on the point, one mid-train, and one ahead of the waycar.  At Keenbrook and Cajon, there were water plugs in the middle of the siding, and at both ends, so that all engines could take water half way up the mountain.  Train lengths then were limited by siding lengths, so the railroad could build the train with the helper behind a certain number of cars and it would stop near the mid-siding water plug.  I worked with lots of steam era Engineers on that territory, and they had some stories to tell.

S.P., of all railroads in the country, really knew mountain railroading, as every line into California had to negotiate a mountain pass to get into the state, and there were mountain grades on lines between the Bay Area and Los Angeles.  In addition, they had very heavy snow removal challenges in northern California and on the Overland Route.  California does not get much rain, and depends on snow melt in the Sierras for most of its water.  And S.P. passed right through the snow belt on three routes. while on mountain grades.  I'm not familiar with their water service, but would be surprised if they did not have multiple water plugs spaced out at certain locations, to allow multiple engines to take water without re-spotting the whole train.

Back in ye olden days, (the 70's) the radio equipment for mid train helpers was carried in a separate (usually decommissioned B-Unit) unit:

Rusty

Southern also had purpose-built radio cars, which operated the diesel units via m.u. connections.