Hi all,

I am slowly re-entering the Marklin HO world after many years. First, I am testing out a bunch of my locomotives on a very simple analog setup without a switch panel. I recently got a 3102 Big Boy but when tested it only runs backwards. Isn't there a switch or something inside the loco that makes it easy to change the direction? Also how can I tell if the loco is capable of being used in a digital setup? There isn't a manual or a manufacture date that I can tell, but the packaging looks to be late 70's--early 80's...

Thanks!

Max

Very useful info. Thank you for your help!

Hi Max,

Welcome to the forum.

Ian.

The Marklin 1985 and 1986 catalogs begs to differ....

Max,

You will find if you open up the loco one wire has come apart from the motor or reversing unit, all depends on the wiring diagram

John

Sounds like the BR53 to me.

The Big Boy is articulated the same way as a mallet (and to me it is one) but is not a compound like most of the early mallets. I assume the BR 53 is the same way. In a compound mallet, high pressure steam is first run through the rear cylinders, then the reduced pressure steam exhausted is run through a set of much larger low pressure cylinders in the front, before being exhausted out the stack. The Big Boy is a simple articulated where all four cylinders get high pressure steam. Is that what you mean?

-James

Max, welcome to the forum!
Thanks for starting this conversation -- you will learn all sorts of fascinating (but possibly contentious, or even useless) things here.
We love it!

Just push on regardless...

Yes John, I have noticed the same, some are great pullers, some are not!
In fact the "poor performers" usually have a problem either with the the articulation (too much friction in curves) or too much stifness in the chassis, which tends to lift a bit the rear chassis.
Try loosening the mounting screws by half a turn.
They are located: two on the bottom, near the front cylinders set, and one on the top, under the rear square shaped removable sandbox on top of the firebox.
The middle articulation needs to freely move vertically by about 4 to 5 mm. (less is a problem)
Usually that indicates some problems with manufacturing tolerances of the said screws.
I have also had a case of a bend tender coupling rod, lifting the power train, and misplaced wiring impeding the coupler's free movement..
Works better now?
Of course, I assume you have checked the smooth running of the "dummy" drivers set first.
Cheers

HI All,

Interesting exchange..a long standing conversation object these articulated , Mallet or not!
Maybe this should be discussed further in the prototype question, but there is a very significant difference between Mallet (compound locos like e.G the BR 96) and the 4 cylinder single expansion ones (like e.g the Big Boy, the hypothetical BR53,etc..)
The Mallet had an inherent flaw in its design!

Running forward, under heavy load, the front chassis of of both tytpes would have a tendency to lift, and starting to slip.

But the Mallet, having their rear HP cylinders' exhaust feeding the front LP ones, the slippage of the front wheels causes suddenly a much bigger steam consumption.
This would immediately create a big drop in pressure at the exhaust of the HP cylinders.
Since the power a cylinder can develop is proportional to the pressure difference between intake and exhaust, there would be also a sudden increase of tractive effort on the rear HP chassis, with the danger that these "shocks" could in turn induce slippage of the rear wheels!
Soon you have a loco that slips from all its driven axles...although the design was supposed to avoid that phenomenon!

So driving a true "Mallet" requires quite a good feel and quick reflexes to cut the throttle as soon as slippage of the front is detected!(Usually, from the vibrations and a sudden change in exhaust rythm,!)
I experienced it myself when I was for a brief moment at the throttle of the little Mallet operated by the Blonay Chamby RR Museum in Switzerland.

On the other hand, the Big Boy and Challengers incorporated a couple of design improvements, aimed at reducing this tendency.
First of all the chassis, albeit articulated, was designed with reinforced pivots and large horizontal sliding surfaces to prevent any vertical movement.
This way, it was much harder for the front chassis to start slipping, having the weight of the whole length of the lok to push it down..
Second, the steam machines being fed independently, slippage in one set, doesn't automatically induce slippage of the other.

Again, having had a chance, for a short while, to be at the throttle of UP #3985 on the Feather River route in California, on the 1991 Shippers' Special, I witnessed that 3985 was easy to control and able to restart the whole consist on its own...without the slightest hint of slippage. ( I gotta exhume the pictures of that event, and share it with you guys, but here is a little preview to give you a feel (The Challenger is the second loco in this picture of a simulated restart with wide open throtles and oil burners!! )

http://www.fotocommunity.../542493/display/19788876


Hope this helps...excite your imagination when you run one of these on your layout!!

Here's the uploaded directly here (note this is a scanned from print analog picture from 1991, forgive me for the poor sharpness)

And the very best place to learn latin too.. My school boy French was improved by Asterix and Oberlix comics of the late '60s and early '70s that were in the school library.. Only comics that were allowed in the library too!