(No photos, alas: my digital camera just doesn’t like taking indoors pics)
Welp, after picking up half-a-dozen or so 51xxes offa eBay, I can definitively answer the question as to whether trolley return loops are practicable.
The answer is a firm, unambiguous, definite “Maybe”.
The main problem is asking a product to do something it really wasn’t designed to do. To recap briefly, the antiderail feature in Lionel electric switches is based on the rails themselves acting as a sort of relay. As the train approaches the trailing end of the switch, the outside rails complete a circuit and the points are thrown in the direction of the oncoming train.
The main problem is in the coils themselves. If the coil is slightly weak, the points don’t get thrown properly. Normally, this isn’t much of a problem. As the loco, tender if any and cars pass over the points, they’re pushed home into the proper position. However, Lionel presupposed that at least eight axles (figuring a 2-4-2 loco and four axle tender) would be doing the job.
If you’re dealing with a two-axle streetcar, all bets are off. [:D]
f you maintain a decorous pace, the points don’t always have enough power for proper operation with only two axles. Even with a sensor track added, it’s not guaranteed that the points will throw all the way.
I will be doing additional experimentation with two sensor tracks per direction; that may be the way to go.
I will say this for the RailKing trolley: The points have to be WAY off to get it to derail. I see it happily bounce over semi-closed points and keep on its merry way…
By contrast, the four-axle Industrial Rail Brill doesn’t like the 51xxes in the least, and derails at the drop of a hat.
So, the answer is: Trolley loops are doable-provding the coils on the switches are in top condition.
Otherwise, it’s an iffy proposition at best.
Very trolley yours,