Bill, don't let Rich get under your skin. Here we are talking about the mating, or lash-up, of the electronics of two toy train engines that have DCS or TMCC so they run together. The train companies use this term in their manuals and to limit confusion, especially for newbies, I think it can be used in discussions like this. However, using consist like Joe did will keep Rich happy.
Anyway, DO NOT USE LASH-UP when talking about running your train, or in operations. To keep me out of trouble with Rich and other members of this forum with railroad backgrounds, I use multiple unit (MU) or consist when running diesels, and double- or triple-headed when running steamers or if each engine has its own engineer at the controls.
In both our cases, the lash-up isn't working and we are not able to run our double-headed engines (or MU) in a train.
If I get banned from the forum I may have to rethink this.