Improving performance can be a bit of a misnomer when the talk circles around modifying a Marklin Z loco or other article in the mini-club line-up. Upgrading 3 pole motors to 5 pole motors is a significant boost to performance, but other improvements may deserve further research and discussion with other railroaders and their experiences.
One improvement I have heard about for many years is actually one I heartily suggest, Glenn and Sandy Stiska of Florida rewired several sets for me in the late 1990’s with this same repair. The modification I am talking about is the addition of two wires to each powered end unit of the VT 11.5 (8873) and the 2 ICE trains including the special release “Amtrak.” For many years this modification has been used with multi-train sets with more than one powered unit. Wired in parallel these early sets were poor runners because they relied on something close to perfection, if the electrical chain was broken between head loco, coaches and end unit the train would not go.
The 8873 used an early conductive coupling which connected the coaches to the powered end units that has since been redesigned: all railcars now use a new flat conductive coupling versus the early spring copper one.
photo: 8873 powered end unit with first generation coupler on left and 88731 Max Liebermann with next generation coupler on right
The original wiring included a pair of diodes for each circuit board which dropped the voltage to each powered car and only allowed each powered unit to go in one direction a contributing factor for stalling the train and/or flickering coach lights if power was interrupted which it readily did. The solution is to bypass the diodes by soldering a wire around each diode thus making it possible for each powered end unit to go in both directions.
A fine point soldering iron is recommended for the repair and just enough wire because too much would interfere with installing the shell.
Try this repair if you have a set of this type that does not run well, the results will blow you away!
Six versions have thus far been released with the last being the “Blue Star Train” with its very striking paint scheme.
Siding: removing the shell of the 8873 is accomplished by removing coupler if it is present and carefully inserting a small screwdriver in the coupler box, if the shell does not easily pop up it maybe stuck to chassis due to hardened oil which will require finessing to unseat it from the chassis, removing the shell from all other VT 11.5’s will require lifting the front of the shell and wriggling it around the permanent coupler. Caution: do not pull on a permanent coupler, it is not removable unless circuit board is removed first.