Better Passenger Train Operation

[Desertdweller]

My N-scale model railroad is built using E-Z Track and switches.  In order to build the railroad I wanted in the space available, I used E-Z track 11 1/4" curves on all my mainline trackage and some secondary trackage.

Being a passenger-oriented operation, I like to run passenger Diesels and full-length passenger cars.  I also like to run some passenger trains that are rather long, up to nine or ten cars.

I use MT couplers, and also a variety of the knuckle types that will mate with them.  MT makes a coupler gauge tool that I have found to be indispensable.  It can be used to set coupler height, track gauge, wheel gauge, and trip pin clearance.

With N-scale passenger cab units, the industry practice at this time is to attach the coupler to the body at the front end of the unit.  The rear coupler is generally attached to the truck.  On the cabless booster units, both couplers are attached to the trucks.

The problem comes when a train is heavy enough to require more than one locomotive unit.  If you run a powered cab followed by a booster, no problem.  All couplers that mate with each other will be mounted on the swiveling tracks.  Thus, they all describe the same arc when making a turn.

But, if you run two long passenger units ( 6-axle) back-to-back, then the nose coupler on the trailing unit (which is body-mounted) mates with the truck-mounted coupler on the first passenger car.  The locomotive coupler will trace a wider arc than the car coupler, leading to a possible derailment.

However, I've discovered that shorter, 4-axle passenger units do not share this problem.  Apparently, the shortness of the unit will allow it to pull a passenger train around these curves by the body-mounted nose coupler.

If you power your passenger train with two cab units, back to back, making the trailing unit a four-axle cab will solve the problem.  So would using a single cab unit, with or without a booster unit.

Back in the seventies, Con-Cor addressed this problem on their E-unit and PA cab units by using the solution used by Lionel tinplate trains.  The coupler was attached to the front truck.  So was the pilot.
This worked, but resulted in the pilots only lining up with the body work when on straight track.

Still subject to experiment:  using two six-axle cab units back to back, with a heavily weighted 40' or 50' express refrigerator car as the first car.  This should have the same geometry as a body-mounted F-unit coupler hooked to a truck-mounted passenger car coupler.

Anybody want to share their own experiences with this phenomenon?

Les

[skipgear]

I'm guessing you are talking about E's and PA's. The simplest answer is replace the coupler with a long shank coupler such as a MT1016. I know for the LifeLike E's that is a drop in and will allow for more coupler swing and solve the problem a lot of times.

[brokemoto]

If you run Kato E-units, the nose coupler that came on them  had a longer shank and it would move a little bit.  That coupler used to be available separately.  I do  not know if Kato still makes that coupler.  I do not know if it will fit the PA.  I still see it at shows.  The Kato coupler will mate with MTs and other knuckle couplers.  it does take a bit of effort to mate them with Unimates.

Full length passenger cars operate best on curves of fifteen inch radius or larger.  If you are going to operate them on tighter curves, longer shank couplers are the key, be they body or truck mount.

[Desertdweller]

Thanks!  MT1016, sounds like something I should try.

Les

[James in FL]

Les,

I've also had good results using MT 1017 trucks on both CC smoothsides and corrugated cars but then I also use 15r min on the main.

http://www.micro-trains.com/trucksCommonwealth4.php

[Desertdweller]

Something else that has helped my passenger trains is to add a little weight to the head-end cars.  This is easy because the design of the baggage, RPO, and combine cars hides a weight placed inside.  For these cars I use 1/4 ounce lead egg sinkers, held in place with either Blue Tack or silicone glue.

Sometimes the cars are just too light to track well.  For cars with windows and interiors, sometimes the egg sinkers can be installed inside the ends of the cars were they are out of sight (try two 1/8 once sinkers, one at each end).

If that doesn't work, try using flat 1/4 ounce wheel weights.  I had some old streamlined cars that seemed just too light to run well with other cars.  I think they were made by Rocco.  These cars use a plastic underframe and a flat steel weight between the floor and the frame.  On the underside of the car, there are two rectangular "tanks" cast into the frame directly opposite each other.  If you use the rotary file bit in a Dremel tool, you can narrow each tank by about half and the flat wheel weight will fit between them against the frame.  Peel the adhesive off the weight and glue it on directly to maximize rail clearance.

A little extra weight inside can improve the tracking ability of non-powered Diesel units, too.

Les

[privprac]

Your right about the radius geometry problem with varying truck sizes. I have not studied or worked on this issue much. But one idea that I've found has some merit, but I can't say in which specific loco-to-car arrangements, is to try longer shanked couplers as this will extend the range of motion. You may lose some of the closer coupling look, but at least the cars won't derail.

Privprac

[Desertdweller]

I think that has a lot to do with it.  I'm doing some experimenting.

Another problem I'm working on is the seemingly inexplicable derailing of some locos on switches.  Some units will run fine over switches, but only when traveling in one direction.  Others will derail when going forward, but not backing up.

Running the chassis through without the body shell on will quickly tell you if interference between the truck and the body is the problem.  But the most common cause is the leading edge of the front truck snagging on the switch.  A little careful filing will cure that.  Taper the front edge of the truck underframe, smooth sharp corners off the switch.

Sometimes, the front truck snags on the loco chassis.  File a little more clearance between the rear of the truck and the front of the fuel tank.  Make sure truck-mounted brake cylinders aren't snagging the bottom edge of the body shell.  Sometimes, on MT coupler converted locos, if the trip pin extends above the top of the coupler it can snag as the truck swivels.  Again, a file will cure it.

One of my locomotives has such long wheelbase trucks, and such a long snout, I thought it would be a nightmare to get through my switches.  Instead, it took them effortlessly.  It is a Life-Like DL-109.

Les