Stalling at the changeover

Hi.

I am looking for help or at least someone who can explain what may be hapening. I have a large layout shaped like an E. the middle prong is powered by a Digitrax controller whilst the top and bottom prongs are each powered by a separate 5 amp booster. Ok, so modern locos run up to the end of a district and across the join with no loss of speed or sound and are totally fine. Then comes my trusty old Hornby Class 37 and it stalls as it straddles the join - as do all other Bo-Bo or Co-Co locos where the power is picked up from one bogie from one rail and the other bogie from the other rail. They don't short anything out but simply stall. Wth enough momentum they can sometimes just about make it across and pick up speed and continue on there way.

Possible work rounds I have thought of include stay alive units and/or additional pickups on each bogie but I would be grateful of any advice or suggestions.

Sounds like a wire link is missing. John Russell of the old Broms Models shop who is a member here may know so I will PM him for you.

I had a similar problem with my Lenz system, but with Hornby Pullmans, not locos. These coaches also pick up from one bogie and return from the other and the lights would go out as it crossed the gap. The solution was to provide a common wire between the two boosters. Not sure how you do this with Digitrax but perhaps the manual explains it. This is what it says in the Lenz manual:  

 
"In some scales there exist locomotives that have pickups that are offset from each other. For example many steam locomotives have power pickup from one rail in the locomotive and the other rail in the tender. When such a locomotive bridges the gap between isolated power stations, the locomotive will stall because the circuit is not complete. The solution to this problem is to provide a common wire between all the power stations. All DCC command control systems need to have such a common provided, if offset pickup locomotives are to be operated."

Hi RFS. Thanks for the response to my query, gave me something to follow up. I checked my Digitrax manuals to no avail so contacted Digitrax help desk and got a response back within 12 minutes - wow. So a trial connection of the GR point on the controller and on the boosters, using a heavy gauge wire, will be attempted when I can retrieve my wire stash from the house next door.

"You can connect the DCS210 and DB210s together with a heavy gauge common wire.  It will not damage anything by doing this.  You are seeing the hesitation because of the power pickups of the locomotives themselves.  Adding the Common may or may not solve your issue."

[user=1886]DaveH_Murcia[/user] wrote:

………………………………………………………………. when I can retrieve my wire stash from the house next door.

"………………………………………………………………….

My mind is wandering Dave ………………………….  :shock: :shock: :shock: :shock: :shock:   Do you, by any chance, use his electric  meter too  :hmm

OK, found some info re a common wire betwen boosters, etc

https://sites.google.com/site/markgurries/home/technical-discussions/boosters/booster-ground-commons

https://sites.google.com/site/markgurries/home/dcc-general-best-practices/booster-connections-power/multiple-booster-wiring
especially this section
5) WHY DO MULTIPLE BOOSTERS REQUIRE A BOOSTER COMMON?

Thanks for the links and help - it's a great help when modelling away from a regular club. I actually found some 1.5mm earth cable in the garage last night which I thought would be adequate to test out connecting the controller to a booster and it works. The class 37 was happy to move across between the two power supplies without stalling. Even though that seems to solve the major issue I still think the class 37 will run much better with a cd drive motor, more contacts and a stay alive fitted. I think it will be a good test to see if it is achievable and if I want to do the same modifications to other "older" Hornby and Lima models. I do have an old Lima Deltic which is really put to shame by the more modern three I already have and hopefully even more so by the two Accurascale ones I have on order once they are released.

I am glad the problem is fixed.

Hi Dave
Glad you found the cause of the problem and got it sorted.

I do agree with you about fitting SAs…..they make a huge difference to the confidence level when running TC

Best wishes

John