What is min radius for coming B&O EM-1?

[LuthierTom]

What is the minimum-radius curve recommended for the soon-to-be-released HO EM-1?

[ACY]

Probably 24 or so, maybe 22, they will likely say when it comes out.

[richg]

What is the minimum-radius curve recommended for the soon-to-be-released HO EM-1?

Couple links I found in a Google search says, 22" recommended. Some will no doubt comp[lain they will not run on 18" radius. A monster like that will probably need the recommended or it will be a display model as one link suggest.
Bachmann still seems to have issues with documentation when advertising.

Rich

[ebtbob]

Good Morning All,

      Whenever a manufacturer states a minimum radius,  it is best that you add 2 inches to that minimum,  especially when speaking about large engines even if they are articulated.    This question was asked several months back and I do not remember Bachmann answering it.    I would think you should plan on a 24 inch radius minimum.  On 22,  the over hand will be enormous and that is not just a visiual issue.   With 22 in radius,  you will need fairly wide centerlines on parallel tracks espcially on the curves.   You will find you would probably need 3 to 3.5 inch center lines.   Also,  you will extra wide tunnel portals.

[jonathan]

Bob gives some good advice.  I have three tunnel portals that will probably need to be widened just a bit to allow the EM-1 to pass through unimpeded. Files and sandpaper are standing-by.

While from a different manufacturer, our club has a N&W Y6b that we run on the layout.  There is a 22" radius turnaround at one end of the layout.  The Y6b negotiates the curve with ease.  It is similar is size (2-8-8-2) to the EM-1.  Because of the way the locomotive is articulated, the overhang is not bad.  It also negotiates normal tunnel portals as well. I anticipate the Spectrum EM-1 will be engineered in a similar fashion and 22" radius curves will be negotiable.

I suggest the Bach-Man has not responded to this point because there is not a finished sample with which to experiment.  I'm sure there are engineering specs, but one doesn't know until there is a finished product to test.

My largest locomotives, so far, are the Spectrum Heavy Mountains with long Vandy tenders.  I can oppose them on my double-track mainline with no problem.  I have a bit less than the recommended 3" distance between the track centers.  I anticipate when the EM-1 is operating, there may not be a train on the opposing track.  So be it.

I suspect we will have to be patient a little longer.  Until then, I will 'anticipate' great things.

Regards,

Jonathan

[Doneldon]

Tunnel portals on straight track shouldn't need to be any wider than what is needed for any other train. Tunnel portals on curves will no doubt be a problem, inversely proportional to the tightness of the curve. That is, as the curves get tighter, the portals will have to be wider. There might be clearance inside tunnels, too, if they are lined and narrow. I don't think many of us line the entire insides of our tunnels but it's certainly not unusual to see 6-12" lined inside of the portals so the trains don't appear to be passing through hollow mountains.
                                                      -- D

[LuthierTom]

Jonathan, I have run Y6bs from 2 different manufacturers (NOT brass) on 18-inch radius curves with no problem, and have run (again, non-brass) N&W A and C&O Allegheny and Texas on 22-inch radius with no problems.  You are right, though, that tunnel portals need to be very carefully placed.

[Doneldon]

The Y6b negotiates the curve with ease.  It is similar is size (2-8-8-2) to the EM-1.  Because of the way the locomotive is articulated, the overhang is not bad.

Jonathan-

The overhang is the overhang. It's possible to manage it to a minor degree but rigid locomotive superstructures of a given length will overhang a given curvature to the same degree. The only thing we have any control over is whether the overhand is mostly on the inside or the outside of the curve. If the engines of an articulated loco pivot near the center of the loco (i.e., the pivots are close to one another) the overhang will be mostly on the outside of the curve. If the pivot points are at the distal ends of the engines the overhang will be greatest on the inside. The degree of inside/outside overhang will vary continuously as the pivot points move in and out, if they could actually vary.

This information is of some value as we plan parallel curving tracks, tunnels, bridges, other structures and even scenery. We can also establish a "rule" such that certain classes of locomotive must always run on the left- or right-hand rails through a particular area or that trains pulled by certain classes of locomotives must have orders to operate on certain sections of our layouts only when both lines are clear. That could complicate things for the dispatcher but the real ones routinely handle such situations. These circumstances don't happen because of locos on real railroads (they happen because of oversized loads) but the operational complication is the same.
                                                                                            -- D

[jonathan]

Doneldon,

Good tip on how overhang is affected by the pivot points on the trucks.  I have noticed on brass articulated locos, the overhang is quite sever on curves.  I think I remember that the rear set of drivers, on a brass loco, do not pivot, causing the boiler front to really stick out on curves.  I have not noticed as sever an overhang on plastic versions, where both drivers sets pivot.

I don't have first hand knowledge of this, just noticed it in pictures.

Regards,

Jonathan

[ebtnut]

In all instances I've been aware of, brass articulated models are built like the real ones-the rear engine is rigid to the boiler; the front engine pivots at the rear cylinder block.  Beginning with the old Rivarossi articulateds
(Y-6b, Big Boy, Cab-Forward) they designed the mechanisms so that both engines pivoted, with the pivot point at about the center of each frame.  This allowed them to negotiate 18" curves with much less overhang.  I believe some other more recent models have done the same thing.  If Bachmann pivots both engines, the EM-1 will likely do 22" curves and maybe even 18".  If they do it ala prototype, then 22" will likely be the absolute minimum. 

[the Bach-man]

Dear All,
22" is the minimum, but the deck plate will bind.  Therefore, even wider radius is better.
Have fun!
the Bach-man

[jonathan]

Thanks, Bach-Man!

I wonder if this means Headquarters has received the first finished samples... perhaps I assume too much.

Regards,

Jonathan

[ebtbob]

Good Morning all,

      Hopefully I did not miss my following point in all the excellent discussion so far about overhang.   In my experience,  the overhang is not as bad as the cab swing.   As my son's BLI N&W Class A negotiates the curves on my HO railroad,  it is the cab edge that will hit the inside edge of a tunnel portal before anything else on the engine.
       Also,  as previously mentioned,  brass models are usually made with only the front engine(set of drivers) pivoting ala the prototypes.   Believe it or not,  this type of articulation(as opposed to both engines pivoting) will require a much larger radius than might expect.   A friend once brought over a brass articulated engine and it hit one of my tunnel portals that is on straight track right after a slight left hand turn.  I was very surprised by this as the curve is easily 26 in radius or better and most engines clear the inside edge of the portal by approx 1/4 to 3/8 inches.  After looking at the situation it was very easy to understand how the rear articulation really changes space requirements of even the smallest of articuled engines.

[the Bach-man]

Dear All,
The tender alone will not negotiate 18" radius.
I've been running it at the iHobby show in Chicago. It runs and sounds great!
Have fun!
The Bach-man

[Keithmoffat76]

Trainworld online says the EM-1 is due in Oct......when will it be shipped to the stores?