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.
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."
Larry Resident Microferroequinologist (at least at my house) Everyone goes home; Safety begins with you My Opinion. Standard Disclaimers Apply. No Expiration Date Come ride the rails with me! There's one thing about humility - the moment you think you've got it, you've lost it...
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.
BaltACD Reliable, affordable communications is the key technology that facilitates the 21st Century.
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.
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.
Jeff
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.
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.
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.
Never too old to have a happy childhood!
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.
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.
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.
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...
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.
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.
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.
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.
You also have to figure out where you're going to hang them.
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.
_____________
"A stranger's just a friend you ain't met yet." --- Dave Gardner
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 think in some places out west in the mountains, they've installed repeaters at some locations.
Using a cable along the telegraph lines or catenary to carry communications between the lead unit and DP remotes would probably get rid of terrain-related comm loss. But it would also knock DP out completely every time snow, ice or trees fell on the wires and broke something. And like Balt said the railroads have been neglecting or removing that sort of legacy infrastructure for many years now.
A better solution would be to switch to ECP braking and use the ECP cable instead, while keeping the current DP radio system as a backup in case of a train separation.
Greetings from Alberta
-an Articulate Malcontent
Erik_Mag SD70Dude Comm loss is a normal part of daily operations, and I believe remotes will continue to perform the last command for 90 minutes after losing comm with the lead unit, then they go to idle. I wonder how well the inductively coupled radio system used by the PRR would bhave with respect to comm loss? One caveat is that te PRR system depended on having some sort of wire(s) paralleling the track, e.g. a code line. Comments on what has been said about radio technology: Sending commands was not a big issue for master/slave being in radio range - I remember ads in a 1964 issue of Model Airplane News for multichannel receivers that would fit in a model airplane. What would take up room is that control logic that would handle the nasty corner cases such as loss of signal that are much more serious for a train than for a model airplane.
SD70Dude Comm loss is a normal part of daily operations, and I believe remotes will continue to perform the last command for 90 minutes after losing comm with the lead unit, then they go to idle.
Comm loss is a normal part of daily operations, and I believe remotes will continue to perform the last command for 90 minutes after losing comm with the lead unit, then they go to idle.
I wonder how well the inductively coupled radio system used by the PRR would bhave with respect to comm loss? One caveat is that te PRR system depended on having some sort of wire(s) paralleling the track, e.g. a code line.
Comments on what has been said about radio technology: Sending commands was not a big issue for master/slave being in radio range - I remember ads in a 1964 issue of Model Airplane News for multichannel receivers that would fit in a model airplane. What would take up room is that control logic that would handle the nasty corner cases such as loss of signal that are much more serious for a train than for a model airplane.
For the past two decades or more - railroads have been investing in the removal of wire lines for either signals, communications or both. What line wires the carriers have not removed themselve, wire theives have removed the wires for them.
BaltACD timz jeffhergert DPs in power maintain the last command for 90 minutes. Is that a typo? 90 minutes, not 90 seconds? Jeff doesn't make that kind of mistake when it comes to operating parameters. While 90 minutes does SOUND like a long time - when you consider the point to point radio characteristics of a lot of territories in which railroads operate - 90 minutes can be used up rather quickly by a train in mountainous territory not going all that far grinding up or whinging down grades with high levels of curvature and virtually no 'line of sight' for radio contact.
timz jeffhergert DPs in power maintain the last command for 90 minutes. Is that a typo? 90 minutes, not 90 seconds?
jeffhergert DPs in power maintain the last command for 90 minutes.
Is that a typo? 90 minutes, not 90 seconds?
Jeff doesn't make that kind of mistake when it comes to operating parameters. While 90 minutes does SOUND like a long time - when you consider the point to point radio characteristics of a lot of territories in which railroads operate - 90 minutes can be used up rather quickly by a train in mountainous territory not going all that far grinding up or whinging down grades with high levels of curvature and virtually no 'line of sight' for radio contact.
jeffhergertDPs in power maintain the last command for 90 minutes.
DPU v1 was manned helpers. Many of those grades were flattened by improving diesel technology, or they were just flat eliminated by post-war railroad and route consolidations.
Post war 263k cars beat the heck out of pre war m.o.w. practices. So track structure and technology had to catch up to the unit trains. And, as noted, Moore's Law eventually allowed for replacing analog technology with digital systems.
DPs in power maintain the last command for 90 minutes. Then they will go to idle and cut out their brake valve. In effect becoming a box car. In dynamic mode, they will stay in dynamics until communication is restored.
A DP in power may go to idle and cut out their brake valve by just making a service application. That warning appears on the DP operation screen. Our instructions used to say make a 10 psi reduction, then it went to 20 psi to force (ensure) the DPs respond.
To force a DP in dynamics to go to idle, you need to stop and make an emergency brake application. Then they are supposed to go to idle and cut out their brake valve.
I think part of the reason distributed power (Locotrol III) became popular is the softwear that automates some of the handling of the DPs. Looking at instructions from the Milwaukee Road's instructions for remote helpers, air brake operation (automatic and independent) was done manually. Now it's automatic. The DPs follow the air brake commands of the lead unit. No more separate buttons for air brake operation. Current DP can also control up to 4 separate DP consists.
Like dynamic braking, it's not just for mountains anymore. DP can help out on the flat lands that are seldom flat. Still, there is a limit to the stresses that equipment can take. Too often everything is figured like it's sunny, 70 degrees, and all equipment is brand new. Reality has a way of rearing it's ugly head to that idealistic view.
blue streak 1 May we wonder that maybe operation of a DPU unit(s) is subject to stray commands? Coud that be why some trains are having pull aparts. Would a stray command of 3-5 seconds be possible to cause a few of these break aparts.? Maaybe road foremans just check the lead loco for commands and not what the DPU received?
May we wonder that maybe operation of a DPU unit(s) is subject to stray commands? Coud that be why some trains are having pull aparts. Would a stray command of 3-5 seconds be possible to cause a few of these break aparts.? Maaybe road foremans just check the lead loco for commands and not what the DPU received?
A remote will only receive commands from the lead unit it is linked to (other remotes linked to the same lead unit will also act as repeater stations and relay radio commands to each other).
Comm loss is a normal part of daily operations, and I believe remotes will continue to perform the last command for 90 minutes after losing comm with the lead unit, then they go to idle. The engineer can force the remote to idle by making a full service application of the automatic brake, even with no radio signal the remote will still see the brake pipe pressure drop. And of course an emergency brake application will have the same effect. Both of these actions will bring the train to a stop, and you can then diagnose the problem.
A remote acting up does have the potential to cause train separations, but bugs in the system are a far more likely culprit.
Improper train makeup and operator error are far more common causes of train separations.
OvermodA part of this is the development of semiconductors and electronics to make reliable, programmable equipment and controls safe and cost-effective. Another part is the railroads having the revenue to spend on equipping sufficient units to allow reasonable operations; some of the cost might be co-assigned to mandatory PTC installation... 'if you're installing those systems why not put DPU equipment in while the locomotive is disassembled for service?'
I can easily be mistaken - with CSX I don't think DPU installations were put on any non-DPU equipped units when they had their PTC equipment installed.
As I have previously stated, all new power that CSX was getting from approximately 2010 onward were equipped for DPU and also the form of Train Control that existed on the RF&P and some other subdivisions on the system.
A part of this is the development of semiconductors and electronics to make reliable, programmable equipment and controls safe and cost-effective. Another part is the railroads having the revenue to spend on equipping sufficient units to allow reasonable operations; some of the cost might be co-assigned to mandatory PTC installation... 'if you're installing those systems why not put DPU equipment in while the locomotive is disassembled for service?'
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