Raait....i had a mystery on my hands here.A couple of months ago,i bought both 39010 and 2 39015's.Never really ran them,as i had a BR03 out a starter set that i normally tested with,and normally i used the class 10 37080 to check for clearances and so forth.

But,ive started my third board over the week-end,and i needed to build quite an incline to get to the sort of effect i need here.Nothing spectacular,but i did climb 20cm in 4 metres.

My measurements show the worst part of it to be around a 5% grade...With 18 coal hoppers behind it,my class 42.9 Franco pulls up there without spinning a wheel.The class 44's even easier.

Just to check i hooked the BR05 ahead of 6 lighted coaches,and it crawled up there without missing a beat.Same with my BR03.Went up no problem.

First BR01 i could lay my hands on was indeed 39010.Ive only run this once before,and i noticed then that it wasnt too bright a puller,and is very sensitive to slightly uneven track.Nothing motor wise,just had very little traction.

Anyways,long story short,neither the 39010 or any of the 39015's would pull my grade.Not even remotely.It wouldnt even go up there with 3 coaches....[:0][:0]

Ive ran my new 39103 a couple of times before,and made it a favourite.It could pull anything the BR05 did....and then some.Its indeed a pretty powerfull puller.Lots of traction,even over uneven track.

Hooked it up tonight,and you guessed it,flies up that incline like its not there.I even hooked 3 more coaches(no lights or extra shoe) behind the 6 original ones,and it pulled up there no problem.The first time it had a little wheelspin(still went over though) was when i hooked the track cleaner behind the coaches.

So....help me out here.They are basically the same locos right.39103 only has the oil tender.But a BR01 should be a BR01 right.....wrong.


So i thought it might be the tender giving 39103 more traction.It must be slightly heavier as it has an extra axle on there,but no way could i believe that.

So i carefully dissected them.Front bogie and drivers,excactly the same.BUT....the rear bogie on 39015 and 010 is 5mm longer than on 39103.

Also if you remove the bogies,the floor pan looks different on 015 compared to 103.

So,just for interest sake,i removed the rear bogie on 39010,and jip....it pulled up that grade with 9 coaches without spinning a wheel!!!!

And ive tried,you cant swop bogies,as the floorpan on 015 touches the wheels on the 103 bogie.

Even with its own bogie,i can see black marks where it touches the floor.All 3 of them have this problem.None of this on either of my 103's and my old 012.

So,i need to ask the question.Why change something that has been working for ages?And did they not test these things?The slightest little change in grade will make that rear bogie take weight of the rear traction wheel.And it just stands there and spins.Helluva frustrating.Is there a cure.I thought maybe slightly smaller wheels,but even with that the top of the bogie itself will touch the floor.

And to scale?Which one was right,or did they differ in real life too?

Im sure,if i remove the rear bogie on the BR45 i will find the same thing.That thing cant even pull itself...

If you look at the train form the side,even on the flats,that rear bogie runs very close to the floor of the cabin.Its just too long.

Your thoughts on this?

Look like you're in for some sort of modification to the rear truck to let it ride higher when it needs to. ....or you could try using a wheel of slightly smaller diameter in that truck. Just a mm or so probably wouldn't be noticeable visually, but it might make the world of difference to keeping the driving wheels on the ground.

cheers
Dennis

Hi Ray....not neccessarily the transition.If i run that train on the flats,the actual space between the top of the bogie and the bottom of the floorpan is 1mm.Its over 3mm on 103.

Here are some of my ideas....either put a little spacer between the chassis and bogie so that it lifts the whole rearend up a bit.

Move the traction wheel to the front driver.

Even the smaller diameter wheel wont be enough,as its less then 0.5 of a mm difference between the top of the wheel and the top of the bogie.

Thirdly and as a last resort,maybe grind a couple of nanometersof the actual floor of the cabin.

I still dont get it.As far as im aware,39010 and 015 were the later BR01's with the 1m diameter wheels.They also had the longer thinner boiler.There is physically very little difference between the locos.

I mean,the BR03 resembles the BR01.10 design very closely on the rear bogie.

I had a look at a friend's BR01 from another make,and it has not got this problem.That rear bogie MUST NOT bottom out.

I have no inclines that start in the corners.

Even a slight dip on a straight will stop it momentarily.

Be that as it may,if i had known that i would need to be a bloody perfectionist,and run these locos on flat track only,i wouldnt even have bothered to buy it.It renders it useless to me.

You obviously have a real problem with this, and I'm surprised that no-one else has reported the same. Having invested in 3 of these locos, you need some kind of solution.

Of your suggestions, I would try swapping the front and rear wheel sets, so that the traction tyres are on the front end. I have an old Br38 (3098), which came with this arrangement. In that case, the motor was mounted very far forward, so the traction tyres needed to be at the front because that is where the centre of gravity was. This might work for you.

Ray

as Lutz says, it is probably more top do with the rate at which your grade changes.
If you place the loco on a 10% slope that is straight, the relationship between the wheels and the chassis should be the same as when it is on horizontal track.

Yes it can be frustrating, but the basis of good running (even on real railways), is well laid track.

Ray

I place a few pieces of card stock under some section and moved piece of track and tightened a few screws.
what was making mine get stuck was the at a section of R1 track with a circuit track and a half section of R1. Each transition was small but just enough to stop the train. Also it just begs to go slow do to the fact that it runs so good at slow speeds so it never has the momentum to get past the bump.
I don't think you can adjust the rear bogie much as the wheel might contact the bottom of the fame.

I hope everyone doesn't miss the important point here being made by Dale and Lutz, as it may escape notice from those not more familiar with prototype railway practice.

Almost every real curve on a railroad has an "easement" into and out of the curve. Most model curves are of a fixed radius. Put another way, model curves tend to be and arc, i.e., circular. Prototype curves tend to be more parabolic, i.e., the radius of the curve gradually increases toward the apex of the curve.

If this still doesn't make sense (and trust me, I RARELY make sense), picture this:

Using C-track (for example), you could lay down a curve using all R3 track sections coming off the straight. Obviously, this would be circular, and have no easement at all.

Now instead, you come off the straight using an R5, then an R4, then an R3, then and R2, and then reverse the order coming back out of the curve. This would be a much more parabolic curve, and have easements into and out of the curve.

Now, a lot of people know this, but the BIG POINT is, all the above is working in the horizontal plane. Easements need to be created in the vertical plane as well!

How to do it with C-track? Not sure, but possibly starting with shorter-length sections and gradually increasing length as the grade is established will give enough flexibility to do this.

To my way of thinking, with people asking for "flexible" C-Track, it would be much better to have a piece of C-Track that's flexible in the vertical plane as opposed to the horizontal plane.

K-Track guys have it made, in a sense. They just need to be much pickier in laying out their track, because they will have to adjust everything, and lay everything out from an approach much akin to what a real railroad surveyor would have to do. I'm sure a lot of guys would enjoy that. Me, I'd go crazy, and I'd much rather be building models and running trains!

DT

Very interessting and good write-up, Riekus! -Thanks!

Hi,

to this beauty here: [:p]



#37115, see attached picture (wheelset on the right; left is from BR01).



PS: The part# you listed above for the BR45 (#37452) contains the complete rear bogie and the wheelset, which has part #104453 and is the same for the BR01 (#39010 etc).

Measures #344420 vs. #104453:

wheel track diameter: 13,8mm - 14,0mm
overall wheel diameter: 16,4mm - 16,8mm

This diameter difference will allow the rear bogie to move across most usual "bumps" and grade transitions w/o touching the loco bottom. The only suitable additional action (besides replacing the wheelset, which is really easy) would be to paint the axle of the new wheelset as well red.

PS: The wheelset on this picture shows the one from the first Württ. C version #3611; the current one from #37115 is a slightly darker red. Another alternative would be to just reduce the outer wheel diameter (wheel flange) of the original wheel set. I checked with the Märklin repair service and got confirmation that they have not seen any such complaint from customers. They also told me that the wheel size differences which I had measured is still within the production tolerances for these parts.

Very interesting Lutz. So if I understand correctly the bogies are the same but the wheel sets are different. However, could you please clarify the part numbers; in your post of 15.5.08 you say 344420, and in your post of 16.5.08 you say 344440.

Actually, on closer examination of the exploded parts lists for 37450 and 37452 they both seem to have the same bogie #219505, but the 37450 has wheelset #343480 while 37452 has wheelset #104453.

I wonder if the wheelset #343480 is smaller than #104453, which might explain the differenc in performance between the two? Or perhaps it is in the other wheels as both models have different part numbers for all the wheels?

I went through great trouble,and switched the rear bogie's wheels with that from my little Class C.

Its still not enough.If i put the smaller wheel from the BR05 in there(thinner axle,so it cant be used)it will pull anything no problem.

Now,ive looked at technical drawings of both BR01.10 and the normal BR01...and yes,both locomotives had a 3.8m span from the middle of the rear driver to the middle of the rear bogie wheel.

So why the hell have they given 39010 and 39015 a longer bogie????