I run an eight car K-Line Heavyweight 18" Daylight Special passenger train. The observation car at the end noticeably wobbles. For the record - any car placed at the end of the train wobbles. What causes this and is there any way to prevent it? Adding a weight maybe?
Replies sorted oldest to newest
If ONE car wobbles I would suspect a truck(s) is loose- slightly tighten mounting screw. If there is always wobbling from other cars when on the end of this train, I have no idea. JohnA
I read recently here that Amtrak puts the baggage car at the end of the train for this reason.
True or not I know not.
Perhaps try switching the order of the cars? Maybe the rear coupler on your penultimate car (which you might always be keeping the same) is transferring motion to the rear car through the couplers?
The last car is less likely to wobble if another car is coupled behind it. The reason is that all cars in a train have the drag of the following car behind it. This drag or pull on it helps keep it in line on the track The last car does not have this effect on its tail end, so it is tail end is freer to sway, bounce and wobble as it rolls along unfettered. The last car of NY city subway trains do this all the time. In Europe and England they, often put a baggage or 'brake van' on the rear of a train, so the last passenger carrying car will have a smoother ride. Of course, passenger equipment over there is built lighter than that used in the US.
S. Islander
I'd add weight to the observation car, that should minimize the effect.
Need to find different passenger clientele...
It's their nature to wobble as they move about!
--------------
More weight might help, but getting the tail car too far afield weight-wise from the rest of the train forward could lead to other operational problems...like string-lining. Probably not likely with the 18" HW K-Line cars, though.
You might try cleaning the wheels of any typical black gunk build-up. More often than not, that black build-up on the wheel tread is not evenly distributed on any wheel, nor wheel-to-wheel.
It doesn't take much out-of-roundness or eccentricity in the wheel/axle condition to induce noticeable wobble, though.
Michael, Someone on our Forum suggested a very small spacer between the rear truck and the underside of the floor. It could be a single wrap(leave relatively long tails so it may be easily removed) of threat/string or the 3/4 x 3/4" piece of plastic which closes the end of the wrapper on store bought bread and bagels. The plastic piece has a slot and the inner portion is round so it may slide in without modifications.
Adding weight addresses the sympton, not the problem. The problem is slack. Adding weight does not reduce the slack, it overcomes the sympton. John
I would add weight to all the cars in the train. That will fix it, and you will be amazed at how adding weight improves their running characteristics.
The National Model Railroad Association Recommended Practice for Car Weight for O scale is:
BASIC WEIGHT: 5 ounces
PLUS
1 additional ounce for each inch of the car's length
An 18" long passenger car should weigh 23 ounces.
Five ounces basic weight plus 18 additional ounces for the car's length.
The PDF file for the NMRA Car Weight Recommended Practice is attached.
@S. Islander posted:The last car is less likely to wobble if another car is coupled behind it...
* * * * *
S. Islander
But then it's no longer the "last car."
Not really cool to stick another car behind the observation car, it's supposed to be the last car in the train.
@Pingman posted:But then it's no longer the "last car."
Then there's that fact, the car you stick behind the "last car" is the one that wobbles! 
Every coupler in a train, except the rear one on the last car, is transmitting a pulling (tension) force to overcome the total rolling resistance of all the cars behind it. The pulling force acting at the rear of each car, except the last, tends to stabilize the car and prevents it from rocking. The rear coupler of the last car transmits zero pulling force, so the stabilizing effect is absent. The rocking motion is not necessarily due to any mechanical issue with the rear truck or wheels under the last car. Adding weight to the rear car increases the rolling inertia (inertia about an axis from the front to the back of the car - parallel to the rails) of the car and reduces the tendency to wobble.
MELGAR
I suppose we could use very heavy grease on the axles of the last car to add more drag... 
I guess this doesn't help with a passenger set but when I run freight I put a diecast caboose in the back so it is heavier than the car in front of it.
I would weight down your observation car to make it heavier.
It's wobbling because nothing is coupled to the back of it to prevent the wobble effect you are experiencing.
I would imagine this is pretty common with larger bulkier cars like passenger cars.
It would be nice if the observation cars in the back were heavier as part of the design to prevent this, but with that being said it seems to be a simple task to do on our own do to there are plenty of different easy ways to weight a car down.
Brad
The rear car wobble is as old as railroading. In the old Steamtown Foundation days we ran a few lightweight Long Island commuter cars, apply nicknamed "ping-pong" cars, in our consists. If perchance one of them ended up on the rear of the train, the reason for the nickname became obvious. Can you say "crack the whip"?
So, weight, as suggested by several forum members, is the best solution.
Earl
Pingman: That is true. An Amtrak conductor told me that when I asked why the baggage car was on the rear of the train. At that time, they would be using both positions: in front it keeps first car away (a bit) from the horn/whistle. I dock by boat close to the Occoquan River bridge, on CSX, and the baggage car is pretty consistently at the rear end.
Back in my working days; I rode plenty of trips in railroad open platform observation cars as well as theater cars at the rear of either solid office car trains or attached to the rear of intermodal trains. The solid office car trains could reach 79 MPH and the intermodal trains 65-70. I cannot recollect ever feeling a whipsaw / wobble effect regardless of train length or speed. Slack yes, whipsawing or wobbling no.
Curt
I'm with you Curt. I've ridden a few business/Obs and older Pullmans on the end of trains at higher speeds. Most would be considered heavy weight cars and most had three axle trucks. They were all smooth riding. Perhaps these attributes, plus higher speeds helped to make the ride smoother. But, boy have I been on some pretty wild rides, especially on trackage limited to slower speeds , say 50 mph and below. Of course track conditions certainly can aggravate the the condition.
I used to wonder if the Long Island's famous "Dashing Dan" had a hard time walking in a straight line to his car when he got off his train. LOL
Earl; I’ve read that the tail car on the GM Aerotrain back in the ‘50’s had a tendency to whipsaw and give passengers a nauseating experience. Perhaps the light construction of the Aerotrain contributed to that if not outright causing it.
I do know that the smoothest riding cars I was on back when I was working were the old six axle heavyweights. I have always been a fitful sleeper on trains with the exception of nights spent on six axle cars. On those I’d actually get a decent nights sleep.
Curt
@S. Islander posted:The last car of NY city subway trains do this all the time.
S. Islander
I rode the NYC subway pretty much every day for about 20 years, and occasionally for another 40, and I never noticed that. Of course, EVERY car in the subway train swayed and bucked all the time, so if the last car did it more, I couldn't tell.
@S. Islander posted:The last car is less likely to wobble if another car is coupled behind it. The reason is that all cars in a train have the drag of the following car behind it.
To wit,
.
LOL! 
There’s no wobbling in that consist, Matt!
Getting back to our original problem with wobbling cars on our layouts, Rich is right, adding weight to most of our rolling stock makes for smoother running. The trains just look better on our less than perfect trackage. I might even suggest that the cars run a little quieter. This thread has been fun and informative. Thanks everyone.
It's the 1:48 scale highballs. Tell the little bartender figure to stop making them quite so strong.
Mitch
@Matt_GNo27 posted:To wit,
.
Good one Matt! 
Most of my consist are passengers.
The Lionel aluminum passenger Silver Dawn to be exact is the only car which has the continuous tendency to wobble the course of the track.
I have attempted to add slim pieces where the truck attaches. I’m just adding trouble.LOL
interesting reading and videos guys….
Interesting that the original poster has not responded to answer any of the questions/suggestions offered.
@Hot Water posted:Interesting that the original poster has not responded to answer any of the questions/suggestions offered.
Appears his just has not logged in since he posted this so he probably will be in for a surprise when he logs back in.
@gunrunnerjohn posted:Not really cool to stick another car behind the observation car, it's supposed to be the last car in the train.
Then there's that fact, the car you stick behind the "last car" is the one that wobbles!
don't know about other observation cars but mine does NOT have a coupler on the read of it
@walt rapp posted:don't know about other observation cars but mine does NOT have a coupler on the read of it
Some do, some don't. You can always use a cable tie.
@B rad posted:Appears his just has not logged in since he posted this so he probably will be in for a surprise when he logs back in.
Logged in? I haven't "logged out" since I joined the OGR Forum, more than 17 years ago.
@Hot Water posted:Logged in? I haven't "logged out" since I joined the OGR Forum, more than 17 years ago.
Your computer is over 17 years old? If you ever changed computers, or even cleared your browser cookies, you would have to log back in.
@gunrunnerjohn posted:He only posted this yesterday, some people don't live with the computer at one elbow.
Agreed. I was just commenting on what Hot Water said by saying the originator of this post hasn't logged back in since this had been posted yesterday.
In running the K-line and GG 17" and 21" passenger consists on wide curves at moderate speeds I have never noticed fishtailing or wobbling.
I would think that the drag induced by axle or wheel wipers would add additional stabilizing??
Wonder if excessive speed and or tight curves might not figure into the offending dynamics??
@Hot Water posted:Logged in? I haven't "logged out" since I joined the OGR Forum, more than 17 years ago.
@gunrunnerjohn posted:Your computer is over 17 years old? If you ever changed computers, or even cleared your browser cookies, you would have to log back in.
@Hot Water blew its cover! It is an AI computer that took over the identity of the original Hot Water almost two decades ago. This would explain its short, sometimes terse-sounding, in-line replies and comments. It's still working on developing its human-sounding responses. For a program written in the early naughts, I'm impressed with its sophistication.
;-)
Back to last-car-wobbles: why is it that none of my "last cars" wobble? (This does not include the occasional car discovered to have an actual wheel/truck/whatever problem.) My layout is old, complete with many barnacles, fault lines and gonzo track work, so it's not because I'm Mr Hot Stuff layout builder (boy, that's a laugh).
@D500 posted:Back to last-car-wobbles: why is it that none of my "last cars" wobble? (This does not include the occasional car discovered to have an actual wheel/truck/whatever problem.) My layout is old, complete with many barnacles, fault lines and gonzo track work, so it's not because I'm Mr Hot Stuff layout builder (boy, that's a laugh).
It could have to do with where you live. If the bedrock is shallow and has a high iron content, its magnetic field could have a stabilizing effect.
@gunrunnerjohn posted:Your computer is over 17 years old?
No, of course not.
If you ever changed computers, or even cleared your browser cookies, you would have to log back in.
Apparently not for the OGR Forum. As we have changed computers, and as often as Apple "up-grades" everything, I have NEVER had to log back in on the OGR Forum. Any and all other forums, yes.
@Hot Water posted:If you ever changed computers, or even cleared your browser cookies, you would have to log back in.
Apparently not for the OGR Forum. As we have changed computers, and as often as Apple "up-grades" everything, I have NEVER had to log back in on the OGR Forum. Any and all other forums, yes.
That's truly odd, every time I clear the cookies of my browser (Firefox), I have to log back in. I haven't done it for a few months, but occasionally I do a "clean-up" and then I have to log back into the sites. I see you mention Apple, that may change the picture, I don't do Apple anything.
Access to this requires an OGR Forum Supporting Membership
