I'm a road engineer. We tried it back in 2007 in Selkirk running east over the B&A, we were still going to Beacon Park back then. At the time they decided the the extra time handling the DP on both sides of the road wasn't worth it.
It usually adds at least an hour and a half in yarding time on my territory on each end. Back then with more trains running, with a 3 hour delay would mean we would outlaw and have to get recrewed.
I wonder if it would be practical to install repeaters on the train itself. If the DPU is 120 cars away, put a repeater on every 20th, 30th or 40th car.
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Paul of Covington I wonder if it would be practical to install repeaters on the train itself. If the DPU is 120 cars away, put a repeater on every 20th, 30th or 40th car.
Much too labor intensive.
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BaltACD Paul of Covington I wonder if it would be practical to install repeaters on the train itself. If the DPU is 120 cars away, put a repeater on every 20th, 30th or 40th car. Much too labor intensive.
Technically feasible, but as Balt points out, labor intensive.
You also have to figure out where you're going to hang them.
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tree68 BaltACD Paul of Covington I wonder if it would be practical to install repeaters on the train itself. If the DPU is 120 cars away, put a repeater on every 20th, 30th or 40th car. Much too labor intensive. Technically feasible, but as Balt points out, labor intensive. You also have to figure out where you're going to hang them...
You also have to figure out where you're going to hang them...
These would be put in the trainline between cars, using the gladhands, and supported from the draft gear much as brake hoses are on well cars.
Supporting repeaters via rechargeable battery is not highly difficult.
The 'materials and methods' used to support FM radio broadcast in vehicle tunnels should work nicely to 'repeater' DP frequencies externally.
OvermodThe 'materials and methods' used to support FM radio broadcast in vehicle tunnels should work nicely to 'repeater' DP frequencies externally.
The equipment to relay public safety communications inside buildings where the signals from the towers won't reach (large steel buildings a case in point) also exists. And this is to handle trunked radio - far more complex a signal than DPUs.
Overmod tree68 BaltACD Paul of Covington I wonder if it would be practical to install repeaters on the train itself. If the DPU is 120 cars away, put a repeater on every 20th, 30th or 40th car. Much too labor intensive. Technically feasible, but as Balt points out, labor intensive. You also have to figure out where you're going to hang them... Actually comparatively simple. They easily go on the units that implement 'midtrain' one-pipe brake release to give a near-ECP service-brake application response. These would be put in the trainline between cars, using the gladhands, and supported from the draft gear much as brake hoses are on well cars. Supporting repeaters via rechargeable battery is not highly difficult. The 'materials and methods' used to support FM radio broadcast in vehicle tunnels should work nicely to 'repeater' DP frequencies externally.
Actually comparatively simple. They easily go on the units that implement 'midtrain' one-pipe brake release to give a near-ECP service-brake application response.
Too labor intensive - especially if the units need to be used more than once. If the units are single use, what will be the incrementing cost over time.
The problem, outside of the mountains, is probably do to the condition and maintenance (or lack thereof) of the DP equipment, including antennas and connections.
Many times, comm problems are solved when a mechanical dept person places a temporary antenna on the locomotive. That also often solves EOT comm problems.
Awile back, I was putting a train together. The DP had already been set up and placed for a rear end DP. When I climbed on the lead set to start doubling up, the head end had already dropped the link and was in comm loss. The mechanic and his supervisor came out.
DP uses two radios, a primary A and a secondary B in case A has problems. The mechanic disconnected the power to radio A. (The mechanic told his super that he didn't see him do that.) This forced radio B to communicate with the DP and it linked. The mechanic said on older engines, this was older and had been recently pulled from storage, the primary radios are getting worn out. Some get to the point where they partially fail, but not enough to get them to transfer over to B. Once linked, the power was reconnected to A. The mechanic couldn't gaurantee it would hold and we could have the same problem later. Since the linking process, including required tests, can take up to 20 minutes, we were told to cut off the DP and go without it. the train didn't need to be DPed, or even that engine for power. Down the road, the next crew would need it if they were to pick up the scheduled tonnage.
If I were going to design a repeater unit for DP or EOTs, I would have an EOT type unit that could have dual air hose connections to supply an air turbine to power it. It could hang on a coupler like an EOT, coupled into the train line. But, as Balt has noted, cost of both buying and/or hanging it will preclude it's use. As long as trouble and failure rates don't exceed the magic number, things are OK.
Jeff
Thanks everybody for a real interesting thread. It sounds like what was holding back earlier use of DP technology was was the technology and size of the equipment required?Old Trains Magazine articles showed Canadian trains going through the mountains with "mid-train helpers". Did those trains also have units on the tail end as well?
Thanks to Chris / CopCarSS for my avatar.
Reliable, affordable communications is the key technology that facilitates the 21st Century.
BaltACD Reliable, affordable communications is the key technology that facilitates the 21st Century.
BackshopExactly. In 25 years we've gone from "portable" phones with limited battery life to much more powerful and compact smartphones with much longer battery life.
We've also gone from portable radios that hung on a strap over your shoulder to handhelds that will fit in your pocket. In fact, the largest part of most handhelds is the battery.
Likewise, we've gone from mobile radios the size of a briefcase to radios that the size of an 8 track player, and smaller.
Now the latest thing is a smartphone that has a folding screen that allows you to fold it up like the old flip phones from 15 years ago.
I always thought the premature demise of the flip phone was dumb. I have no desire to carry a phone that's damn near the size of an ipad and barely fits in my pocket. I hung on to my old flip phone as long as I could, and I'm happy to see them make a comeback.
Backshop BaltACD Reliable, affordable communications is the key technology that facilitates the 21st Century. Exactly. In 25 years we've gone from "portable" phones with limited battery life to much more powerful and compact smartphones with much longer battery life.
Exactly. In 25 years we've gone from "portable" phones with limited battery life to much more powerful and compact smartphones with much longer battery life.
With so many @#%^$&@ apps that I don't need, or want. Some of which operate in the background using up the battery.
I have one of those old shoulder strap Motorola radio sets. It was in a local antique store a few years ago. I can't prove it, but with the store being located in the home terminal for railroad crews - one that was much more important when the radio would've been new, there's a chance it was used by the railroad. That's my excuse for buying it.
Most of the reduction in size of portable radios and cell phones IMO is the development of compact fractal antennas. Much less power needed for transmitting or receiving. It is not broadcasting any more but narrow casting. Some with frequency hopping.
blue streak 1 Most of the reduction in size of portable radios and cell phones IMO is the development of compact fractal antennas. Much less power needed for transmitting or receiving. It is not broadcasting any more but narrow casting. Some with frequency hopping.
With portable radios, the move to IC's and digital sythesizing of RF has had a huge effect. A sixteen channel radio would have required sixteen crystals, coils, and other large components, even at five watts. There's a reason why early handhelds were often referred to as "bricks."
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