Easy child, easy!
A "Proctor" in the USa is the person who oversees tertiary examinations.
I can quite understand that that would be outside the realms of Twibel's
experience or understanding and that he would confuse "proctologist", being
as how he is so anally focused, but I had expected better of you.
Regards,
Greg.P.
The German railways (seven State railways) agreed in 1908 to fit all
goods wagons with air brakes. The same standard was accepted by all
European Interchange Treaty members circa 1910.
From then on, all new wagons were built were either fitted with full
air brakes or through piped for airbrake operation.
Existing wagons were modified at the time of major overhaul or
withdrawn from the pooling system.
Of course there was a war from 1914, depression from 1918 (which resulted
in major down-sizing of rolling stock rosters until c1930), the US
depression from 1928 (which further affected Europe) and another WW
in 1939. In German at least, this meant that the last non-air braked
or through fitted wasn't withdrawn until about 1953-54.
By 1932, which is the year I happen to model German Railways, unbraked
and unfitted wagons were becoming quite rare.
Regards,
Greg.P.
Existing air brakes systems are fail safe:
http://www.railway-technical.com/air-brakes.shtml
http://en.wikipedia.org/wiki/Railway_air_brake
HTH
wolf k.
...
Yeah, I know, but I do see one problem with fully automatic couplers -
as explained, they may not "open" the brake line in case of unwanted
train separation at speed or they would "open" the brake line in case of
(controlled) hump yard shunting...
So, two different ways of uncoupling have to be implemented:
(1) "controlled" uncoupling with the valves closed before uncoupling the
brake lines and
(2) "unwanted" uncoupling with the valves staying open long enough to
put the train into emergency braking after uncoupling the brake lines.
But I'm sure the designers of the system did thing about this ;-)
Ciao..
In the case of a "break-in-two" at speed, the brake lines certainly
would open, albeit destructively: the hoses would simply be ripped from
the trainline.
--
Found--the gene that causes belief in genetic determinism
On Fri, 04 Sep 2009 05:12:24 +1200, David Nebenzahl
The European center coupler had the airlines and several dozen electrical
connections mounted on the "glad-hand" so that they connected
automatically.
Presumably uncoupling disconnected them automatically?
With the precision engineering to eliminate almost all the free slack and
all those automatic connections, it was an expensive coupler and that's not
counting the cost of wagon conversion.
Knowing about how hump yard operations are done would help!
Humpping a car is done with the car's braking system empty or closed off.
If they were to have pressure in the brake line for the hump car cut, the
cut would stop each time a car was disconnected and that would be one big
mess! The braking system on each car is isolated or otherwise disabled
while the hump operation is being done with the strong tendency of the
system being emptied of air. Otherwise, when it comes to moving the cut
after connecting the brake lines and opening them prepatory to charging the
system, the cars that had air in them would be locked solid to the track
until the pressure in the train line got high enough.
--
Bob May
rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net
The trade-off is rougher riding and more damage to freight.
A worker or two written off every year against a high number of damage
claims?
;-(
Any time there's a spring there's compression available, but a properly
tightened Euro train doesn't have the 10cm slack between each wagon of
the historic British train nor even the 1/4" to 1/2" slack of the US cars.
Loose slack is different to sprung slack as far as damage to contents is
concerned. The unloved Euro automatic center coupler was still going to
have circa 1mm slack and increased damage claims were a considerable
concern.
I used "black and white" phraseology as adding all the greys increases
the text by a factor of 10 or so ;-)
Not sure whether the Euro center coupler addressed that or not. It was to
be automatic in connecting all functions. Broken brake lines should have
been simple enough to detect - there's two great big couplers connected
or not!
Looks to me as though the whole scheme got too expensive to complete, so
they failed to start.
Hi,
Greg.Procter wrote:
(center couplers vs. buffer-and-screw)
Not necessarily...
Well, in a badly tightened train I'd say up to 1/2" of loose slack and
some more slack at the point where the buffers just start to compress
until they reach the "norm" compression, so about 1" would be what I
often see a freight train's rear wagons "bounce" back after stopping,
accumulated to more than 1ft. in a normal (10-15 car) train...
Especially fancy to watch when it's tank cars that are about half full...
Well, I'd consider 1mm of slack to be less than what I regularly see (or
think I see).
Apart from that, you can build a center coupler with some buffering
properties (spring), and this is being done with Scharfenberg couplers.
So basically you could have little "free" slack (a few mm) and some
sprung slack (which would negate most of the free slack). But this is
more expensive than...
Sure ;-)
(automated brake line coupling)
Yeah, but my argument was along the line of a few wagons separating from
the end of a train at speed - the automated valves need to stay open for
long enough to put the whole train (both parts) into emergency braking -
as would happen when a train separates nowadays)... But if the brake
valves shut upon the separation, both parts of the train would continue
to "run" at speed which is not good ;-)
That was about the point - it would have been too expensive to change
millions of couplers...
So, I have all winter to either change my model railroad's couplers
(N-Scale Rapido to Kadee-style) or to repair my broken Rapido couplers ;-)
Ciao...
One can make "hooking up" automatic but accidental uncoupling (or
deliberate
uncoupling) manual.
We have "pre-uncoupling" available in HO scale!
You could invent something better!
I use Rapido coupler (heads) on my HO British rolling stock. The slack
is about right to represent the slack of historic British goods trains. ;-)
I tried HO Kadees but they required nasty alterations to the wagons,
and the Rapidos will couple to HO NEM couplers if I ever want to do that.
Regards,
Greg.P.
[snip]
For UK operations up to 1970 or so, the reference is probably "Freight
Train Operation for the Railway Modeller" by Bob Essery
(Amazon.com product link shortened)
Tim
Polytechforum.com is a website by engineers for engineers. It is not affiliated with any of manufacturers or vendors discussed here.
All logos and trade names are the property of their respective owners.
