Apparently all solenoids are NOT created equally. We all have seen solenoids used in many different accessories like the 145 gateman, 252 crossing gates, and certainly in switches. Otherwise identical accessories can behave quite differently when differences in the solenoids exist.
Most solenoids seem not to be linear, that is their plungers don’t maintain a constant push/pull force along the entire travel of the mechanism - generally they seem strongest when the plunger is halfway out of the coil, or so it appears. I have one solenoid that can just barely push the plunger until it reaches near full extension, then WHAM! It absolutely slams it home!
I have encountered different DC resistances within otherwise identical coils, an issue that always sent me looking for bad/corroded connections, bad solder joints, etc., but rarely successful. That always left me wondering had there been a design change in that accessory somewhere along the way?
Many of the solenoids I have seen appear to be nicely wound until the last minute, when it looks like the winder grew weary of his task, and just let ‘er rip!!!
Some of the 1122 switches have plungers that have a smaller diameter extension of the plunger that engages the bent wire that attaches to the switch mechanism - that smaller diameter area on the plunger seems to produce a VERY noticeable drop-off in push/pull forces when it enters the coil.
I would appreciate hearing the experiences of others on how, or if, you have been able to produce a more linear push/pull, or otherwise strengthen a very weak solenoid. I think cleaning the plungers and the coil interiors may be a given - so what else has worked for you?
