Yes, roller bearings do make the job a fair bit easier than with the older
friction bearings but the problem is still there. I don't know how many
cars you may have in a train and how heavy those cars are when loaded but
back when Krauss-Maffei did the 6 locos for the SP and D&RG railroads, they
could only test one loco at a time and even then couldn't get the full power
out of the loco due to the lack of ability of the train to take the strain.
Over here, the locos ran in 3 unit sets, often with another loco(s) of the
diesel-electric type to move a train on the SP and D&RG railroads.
Stretch that train out and try to start it and there will be a whole lot of
power needed to start it moving. Diesels can often get them rolling but
steam engines definitely couldn't even today with all of the roller bearings
on the axles.
rmay at nethere.com
http: slash /nav.to slash bobmay
http: slash /bobmay dot astronomy.net
I think that was standard practice in the days of steam, when an engine
could pull a train it couldn't start. There was an advantage to back a
short distance, then start the train one car at a time.
Anyone else remember the sound of a long train starting? The bang at the
head end as the slack was pulled out, then the bang bang bang as the slack
pulling moved down the train. That's something you don't hear any more.
In the case of historic British coal trains, that was the norm. Their
trains mostly were pulled by 0-6-0 tender locomotives right up to the
That was all that was required to move the maximum length trains
allowable. Of course they could only achieve something like 15mph and
spent most of their time in sidings waiting for 60-100mph passenger trains.
Using Opera's revolutionary e-mail client: http://www.opera.com/mail /
Britain used non-screw (3 link chain) couplers on it's goods rolling stock
from 1800 to the 1960s.
That it lasted so long was due to private owner (coal) wagons being
standardised in 1923. (rough handling was hardly a problem with coal)
Screw couplers on other goods stock was gradually introduced in the 19th
and 20th century.
Funny that you say that - after all Thomas the Tank Engine *IS*
modeled after British prototypes (which are equipped with buffers).
To Europeans Thomas looks quite correctly modeled (not just some silly
cartoonish toy with buffers).
I can also relate to what you feel but in reverse. I grew up in
Poland (in the 70s) and I had mini TT gauge layout (using buffered
European prototype of course). When I arrived in the USA and started
researching the local railroads and then modeling US railroads in N
scale they all looked really funny without buffers. To me they didn't
look like real trains as they were not equipped with buffers! US
boxcars looked more like trucks on track than real railroad cars. At
this point I got used to that look but when I look at some of my
European prototype models, those buffer equipped models still look
more "railroady" to me than US prototypes.
I do however remember some examples of bufferless rail vehicles from
my days in Poland. All the modern trolleys used center couplings (and
didn't' have buffers). Also IIRC, certain types of local commuter
multi-unit trains had what looked to me like automatic center couplers
(and no buffers again). Those couplings were used to couple several
of permanently coupled multi-unit consists together.
Did I say "it's always been done so"? Back in 1840 European trains
started out with side buffers and coupling chains (a short piece of
chains and a hook at each wagon!). Over time, they developed "three link
coupling" - basically three chain links, no more, no less. Still with
side buffers. Later on they found out, there is too much slack in three
link couplings, but by then the chains were often attached with a pole
from beside the wagons (no problem if you have loose chains). So they
developed a special link (the middle one in the chain) which needed to
be turned after coupling the train. This did reduce slack but did not
eliminate slack. The logical next step is the screw arrangement in use
today, couplers can be tightened enough to compress the buffers and to
allow for (almost) no slack. This works fine and has been in use for the
past fifty or hundred years. But then the guy has to go between the cars
to do the coupling - we talked about that...
Now, go back to about 1900 and take the ship to North America. They were
running longer and heavier trains than the Europeans (or wanted to) and
they were facing the same problem. What the Americans did, they changed
the system completely (not just improved it). They moved the buffer to
the middle (need only one, not two, save money ;-) and put the coupler
right into the new buffer (even less parts, even cheaper, save more
money). The design (which is still used, though in improved form) was
the most advanced one back then and serves today's railroads quite fine.
So you see, most of this has historical reasons ;-)
Now come the "modern Age" - European railroads found out that there is a
serious drawback with the hook-and-screw couplers: if you're running
passenger trains and want one part to stay on the main line and another
part to run the side line from a certain station on, that's highly
impractical (this concept has never been used much but is gaining
popularity now). So they adapted center buffer couplers as well, but -
being Europeans - they wanted the "BEST" design possible. The result is
the "Scharfenberg" type coupler, but they did NOT design a common
standard for it. There is actually only one company to produce the
design, the couplers are (comparatively) complicated and thus are
expensive. So they only get used in an insular fashion - the problem
with broken-down trains has been mentioned.
Now, just for the fun of it, take a look at Russia. Their couplers are
similar to the Janney couplers, but they use a different mechanical
design. I don't want to say it's better nor worse, just different. Check
it out on Wikipedia if you like. Basically the Russian type coupler was
discussed for europe-wide adaption, but they wanted it "gold-plated" and
with all extras for the cost of nothing. They did research a feasible
design with air and electrical connections, (they even made provisions
for reducing the possibility of derailments) but it was expensive. So,
as you'll guess, it never got adapted...
By the way, there will always be a little slack between the wagons, but
in today's railroad couplers it is reduced enough (if they get used
correctly). It's a relative question, an inch is not much in a
several-hundred-feet freight train, but it might be too much in an
high-speed passenger train...
Now, to get back on-topic with the model railroad theme... Consider the
coupling problem solved with knuckle couplers. They could even be
applied to models featuring side-buffer imitations, but you'll rather
find *huge* (and ugly) hook-couplers (HO) or Rapido-style (N). The
wagons will sport side-buffer imitations ;-) And the hook couplers
resemble hook-and-chain vaguely ;-)
On Thu, 23 Oct 2008 07:01:03 +1300, David Nebenzahl
The advantage of the side buffers is the elimination of slack, and the
resulting damage to goods.
The planned Euro centre coupler was to be the ultimate in fine tolerances
so that the inherant slack would be negligable, but of course that level
of manufacturing tolerance costs!!!
Even with side buffers and screw couplers you will have some slack
(although only little). It is still possible to back up against a train
(compressing the buffers) and then start forward (releasing them). You'd
have to tighten the screws quite a bit to prevent that - and then the
buffers would resist the train going around a curve.
So I'd say that with screw couplers and buffers (european style) there
is very little "free" slack, but still a bit of "sprung" slack.
If handled carefully, a bit of slack is no problem, but you wouldn't
want excessive slack in a high-speed-train. It's all a question of
Well, there should have been *very* little "free" slack (you still need
a bit for the locking plates to slide into place), but you still need
the coupler mount to include a buffer. Again, the buffer needs to have
some movement allowed which you could use instead of slack ;-) Compare
the Scharfenberg couplers - they are close-tolerance meant to fit the
form of the opposite one. They even use a sophisticated locking
mechanism which "pulls" them together. But when coupling several
four-car 130-ton multiple units you definitely need some buffer and you
need torsional as well as lateral freedom which makes a very complicated
coupler shaft. You wouldn't want that coupling to be completely rigid ;-)
Back in the days when I stood on open end-platforms and watched the
coupler action, I noticed that occasionally the buffers on the outside
of the curve would part. The screw couplings weren't tightened enough, I
Two points there:
- depending on the design of the buffers, some are/were sprung with a
semi-eliptical spring behind the two buffers which will equalize on
curves. Others have/had self contained coil springs.
- On lines with tight curves and with rolling stock fitted with
self-contained spring buffers the couplers wouldn't be tightened all the
way. If the buffers reach the end of their travel those 4 wheel coaches
could derail. (on the principal that something has to give somewhere)
Standard method (see other posts.)
However, many passenger cars now use centre couplers, some even with
buffers. Most are multi-connection couplers, see photos of UK DMUs on
alt.binaries.pictures.rail for examples.
British rail installed fold-down knuckle couplers on Mark 1 or 2 cars
IIRC. These cars also had the screw couplers. Most Britsih DMUs have ths
Wait a second, automatic center couplers are seen more often, but mostly
in multiple-unit-trains (to ease coupling) and on train end wagons (such
as the remote cab in two-way-trains. Again, they are meant to speed up
coupling passenger trains. At least in continental Europe, passenger
cars still use the screw-type couplers between each other.
On the other hand you'll find permanently coupled multiple units with
central couplers at the unit ends more and more often (e.g. with Jacobs
bogies). They don't use any couplers internally ;-)
This may actually lead to considerable confusion because the center
couplers (Scharfenberg type) are available in different types with
different positioning of electrical and air connections.
In general the whole situation is quite difficult in Europe, there are
national regulations (the brake pressure gauge needs a red needle in
Germany and a yellow needle in Italy, e.g.), european regulations and
many different established solutions. While there are different
regulations in the american network also, at least the interfaces
(couplers) are standard. And I do think, that the Janney couplers are a
good solution (while not the best possible). The europeans missed each
and every chance in history to adapt something similar... Like I said,
nice people individually ;-)
http://commons.wikimedia.org/wiki/Railway_coupler shows several different
looking Europena couplers and I don't think any of them look automatic. But
I must confess, I've never seen European trains in operation either.
I can't speak for continental Europe but in Britain the majority of
passenger trains are multiple units, with automatic couplers to permit
several units to be run as one train.
Some longer-distance passenger trains are loco-hauled but these are
operated almost as if they were multiple units; they often have
semi-permanent couplings between vehicles and are not routinely
uncoupled or rearranged - only for maintenance or to deal with
problems (eg to swap out a failed loco). These trains are too long
to run in multiple-unit formations.
For example, the Class 365 trains which run between my home city of
Cambridge and London. These are 4-car units which are very frequently
coupled and uncoupled while in passenger service; many of the fast
trains from London are 8 cars which run non stop to Cambridge and then
divide, with the front 4 coaches carrying on to King's Lynn - and of
course in the other direction, a 4-car unit from King's Lynn will be
coupled up to another 4-car unit at Cambridge. This takes only a few
minutes and a minimum of staff.
Wikipedia has a pretty comprehensive set of basic information about
British trains at pages named like this:
All European high speed trains (all trains >250kph anywhere?) have
automatic couplers although the coupler itself is obviously covered by
a panel when not in use for aerodynamic reasons. Certainly the French
operate many services with two TGV sets coupled together although I
don't know if they routinely uncouple/recouple at the platform, rather
than in a siding or a depot, or even do it with passengers on board.
Ian Jackson personal email: < firstname.lastname@example.org>
These opinions are my own. http://www.chiark.greenend.org.uk/~ijackson /
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