Currently thinking about adding DCC to an ABBA Proto E7 mashup. Only the A Units are powered, the B Units are dummies. Is there anything I should pay attention to besides having the same adress and settings for both decoders and wireing the front A to run forward and the rear A to run backward? I somehow feel uncomfortable having 2 unpowered and much lighter B Units in between 2 powered and heavier A Units, always fearing that the rear A Unit could push the B dummies against the front A Unit...
You definitely can run dummies between powered units.
On "wiring the rear A to run backward", just wire both A's the same so they run forward when your throttle is running one alone. When making up the consist, just set the appropriate CV for the rear A unit (nose backward) to tell the DCC system that one runs backwards when the consist is running forward.
On the weight issue, I did have a bit of issue with an A-B-A E6 P2K setup where the B unit derailed on occasion. Not sure if the rear unit was running a bit faster re: speed matching but not much. I simply added a bit of weight inside the B unit (a couple of hefty steel nuts). You may not need to do that, so wait and see.
Paul
Modeling HO with a transition era UP bent
I'd agree with adding weight to the B unit if it's too light. My dummy B unit is an old Athearn which was built on the same metal chassis as the powered unit, so it's fine.
I like to put a sound-only decoder in dummy engines.
It takes an iron man to play with a toy iron horse.
I've had lighter freight cars between the loco and heavier cars, and on the club layout, which is I think 28" radius, I can do very jerky jack rabbit starts and stops and they never come off the rails. With proper train handling, not a chance. I don;t think there will be any problem as-is. Go ahead and add a little weight to the B if you think it needs it, but extra weight added to the B unit is fewer cars the two powered A's can pull. Maybe that's not an issue either, as most A units can pull more cars than a real one, and two powered units can haul a long train indeed.
--Randy
Modeling the Reading Railroad in the 1950's
Visit my web site at www.readingeastpenn.com for construction updates, DCC Info, and more.
De Luxe I somehow feel uncomfortable having 2 unpowered and much lighter B Units in between 2 powered and heavier A Units...
I somehow feel uncomfortable having 2 unpowered and much lighter B Units in between 2 powered and heavier A Units...
Alton Junction
Well, the point is I need that mashup for pulling a 12 car passenger train which is made up of 2 Walthers Proto Smooth Side cars, 5 Walthers Mainline Corrugated Side cars, 4 Rivarossi Smooth Side cars and one IHC Corrugated Side car. All cars have full interiors, passengers and interior lights. Quite a heavy train. Normally an ABB mashup would be prototypically correct for this train (and eleminate the possible problem of B dummies being pushed against the front A Unit), but I fear that a sole A Unit won´t be able to pull the train alone and therefore requires help of another powered A Unit (the Units haven´t arrived yet so I couldn´t test it).
Just make sure You weight the B's......close to what the A's weigh. Speed match the two as close as You can, a few RPM's won't matter. Put the faster one at the rear.
I run DC with a ABBA consist......Walthers Proto F3A powered, Intermountain F3B powered, Athearn BB F7B dummy extra weight with NWSL wheels and a Athearn F7A powered with NWSL wheels, along with a ten car Walthers 85 ft Mainline line cars with added interior/lights. Also the whole train is close coupled with diaphragms. The lead engines have a 14 to 1 gear ratio and the Athearn F7 has a 12 to 1 gear ratio, they all start at the same speed......but the Athearn does have a higher top end speed, but they all run great together, not a problem. Just for giggles, I put a CMX track cleaning car filled with lacquer thinner in the front and they even pushed that around the layout with the full train. I have all broad curves on the layout and havn't had any kind of derailments yet! Power comes from MRC CM 20's used solely for engines, nothing else.
Take Care!
Frank
Ok, you guys gave me some hope now. On my future layout, I don´t plan to have any grades steeper than 3%. So I hope that the powered A Unit with 2 light B dummies in tow can still handle my 12 car Golden State train! By the way 11 out of 12 cars roll super free as only the last car has the electrical pickups, as the power is being transfered from to car to car by double plug connections. My MTH SP GS-4 4-8-4 has no trouble at all with this consist, so I really hope that my Proto RI E7 ABB mashup won´t have troubles too! Would be great if I wouldn´t need the second A Unit!
De Luxe Currently thinking about adding DCC to an ABBA Proto E7 mashup. Only the A Units are powered, the B Units are dummies. Is there anything I should pay attention to besides having the same adress and settings for both decoders and wireing the front A to run forward and the rear A to run backward? I somehow feel uncomfortable having 2 unpowered and much lighter B Units in between 2 powered and heavier A Units, always fearing that the rear A Unit could push the B dummies against the front A Unit...
Yes, the SR pulled the Crescent by 4 E8 A Units and the UP City of Everywhere required even 5 E9 Units in A-B-B-B-A lashups. But these were exceptions because of what you wrote. As ar as I know RI always used either A-B or A-B-B lashups on the Golden State. Never more than 3 Units because it simply wasn´t necessary because of the relatively flat territory. So I really hope one powered Proto E7 can handle it...