NOSE-TO-TAIL STORAGE/STAGING - PART TWO

We are running DCC trains on our layout and we have them in a storage system that runs them nose-to-tail. Can we do this with TWO or more NCE MINI PANEL micro-controllers?

Thomas along with Annie and Clarabel have run into our storage system.  They ran up to our blue sensor and were held there for a while by the red MINI PANEL conroller.  Now it is time for them to run out onto the mainline, and run at faster speeds controlled by a second MINI PANEL that we will call green.  In this image Thomas is crossing over from one section to the other.  If this were a DC world, we could accept this practice. For a brief moment there is a blip while the locomotive straddles both sections and some of the higher voltage green section bleeds back into our lower powered storage section.  It does not create too much fuss.

BUT, in a DCC world, while Thomas is straddling the two sections, and allowing the digital commands to mix, another locomotive being held in storage may have seen a command issued by the green controller for it to run faster. Once Thomas leaves the section, that locomotive may continue to hold-on to that erroneous command, and 'run-away' at faster speed into the back of another stored train.  Obviously we cannot allow this to happen!

So we need to factor in a 'handover' period where the red controller takes charge of part, or ALL of the mainline for a long enough period so all locomotives in the train reach the mainline section, before the green controller takes over.

It is possible to have a short section of mainline track wired to accommodate this HANDSHAKE period, long enough to accept the length of your 'head-end' power [one, two, three or four engines].  Including this section of handover-track, avoids having to give control of ALL the mainline to the red controller.

However, some layouts will feature trains with helper or bank engines spread throughout the train, or bankers on the rear; in which case the delay will need to be much longer, until ALL of the train has passed the sensor; and then allowing a further few more seconds grace period after that.  If you have a handover section, that may need to be long enough to accept your longest train. 

Consider that some passenger trains may also have power units front, middle and/or rear, AND the wheels/tyres of some coaches with lighting will also manage to straddle the gap between sections, creating the same cross-contamination.  My XPT will keep oscillating. It will have power at the front-of-the-train one trip, and rear-of-the-train on the next outing.

Success!  Thomas has made it safely into the new section. The HANDSHAKE is over, the green controller is fully in charge now, and Thomas may now run at mainline speed, and he won't be meddling with the decoders of any other engine held in the storage sidings.


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