On the topic of overhead (“live”) wire at the gaps between modules, I was reading a very old (1949) MR yesterday and there was an article by HO pioneer Eric La Nal (pen name for Allan Lake Rice). He had overhead wire at a “lift bridge” that was needed for access to his layout interior, versus a duck-under. He was stumped by how to have the wire be seamless at the gap, which would be very like the situation at a modular traction layout.
The solution was to do what the prototype traction/trolley systems did in some situations: the wire ends in an inverted V channel which would hold the trolley in place and supply current until it could meet its counterpart V channel to supply power and hold the trolley wheel in place until it met wire again.
It would be difficult to have two ends of wires so precisely formed that a trolley pole could bridge the gap and still have the wheel under the wire. But the V channel would provide power and force the pole’s wheel (more often just a shoe, in HO) to be under the wire where the channel ends.
The prototype would use these similar V channels to force trolley poles down yet still supply power when a street car or other traction equipment with a trolley would enter a car barn or other low clearance, where the interior wire was at a lower level than outside.
Dave Nelson
Dave Nelson
If you are not going to run wires, the solution could be to simply build the catenary to clear the double stack traffic. In the real world, it’s unworkable simply because you’d need a ridiculously high pickup. I assume that is why I don’t see any double stack under wire in the Northeast Corridor. There when you get to a lift or draw bridge, the wire stops and the momentum of the train carries it across the dead zone.
On the subject of electrics, I thought the NYC electric zone was clever as they use a low mount third rail accessed with a shoe off the locomotive truck to provide power. It is well insulated from casual contact and well marked as to it’s danger though Darwin still wins on occassion (hey watch this!). I think in fact that many of the early (prewar) O scale layouts used the same concept to get away from a third rail in the middle of the tracks ala Lionel). But now I’m getting [#offtopic]J.R.
GMT wrote: “If you are not going to run wires, the solution could be to simply build the catenary to clear the double stack traffic. In the real world, it’s unworkable simply because you’d need a ridiculously high pickup. I assume that is why I don’t see any double stack under wire in the Northeast Corridor.”
I don’t believe double stack will FIT under the NEC catenary – trail vans, yes, but DS is higher.
When double stack first started, the only route possible into northern Jersey was via the old Erie Southern Tier Line. As the Erie was the former “high and wide” route (a legacy of its early days with 6’ gauge), nothing had to be “raised” – the trains just ran. Got to run at least one myself, as I worked Pt. Jervis to North Jersey now and then.
Later on, they got clearances opened up on the River Line and the Mohawk, so the stacks started coming in that way…
I don’t think I’ve seen Superliners on the NEC. In NY Penn Station I’ve seen Viewliner cars, but that’s about it. There’s freight at times on the NEC, just never seen any type of intermodal action.
Superliners can’t fit in the NEC. In addition to wires there are also tunnels that block max height cars from entering the NEC. That’s why only viewliners and amfleet cars are used by Amtrak there, and all intermodal stuff runs single stack through the NEC.
So it appears Superliners can fit under wires! I will then conclude that the reason they aren’t used on most NEC trains is because of clearance issues coming in to New York City. The Lake Short Limited and Silver Star/Meteor for sure use single level stuff for that reason.
The video may be deceiving. Trains have to back into the station and I don’t think all tracks have catenary. Hopefully someone can confirm?
It’s looks like there is at least wires to hold up catenary on the other track, but I can’t tell if the catenary is also over the Superliners. It’s really hard to tell!
SPSOT wrote: “So it appears Superliners can fit under wires!”
The catenary on the NEC isn’t the same height everywhere. The clearance underneath varies, it becomes much tighter under bridges and in tunnels.
Down around DC, there’s enough clearance for the SuperLiners, as seen in the video.
You wouldn’t want to try to fit them into NY Penn Station, though !
PRR_CT-290_0001 by Edmund, on Flickr
PRR_CT-290-crop by Edmund, on Flickr
Excellent view showing clearance above Superliner equipment:
https://tinyurl.com/y2zzkwxf
Cheers, Ed
I have not built any yet, but have modeled heavier constant-tension cat designs and have a couple of potential suggestions:
Model the catenary as actual constant’tension with weights and use ‘scale’ thin material like Vicryl for the actual ‘tensioned’ member in the wire, with formed stiffness in the hangers and catenary curve. Arrange some kind of anchor or signal bridge at the edges of the module if you plan on displaying it ‘alone’; otherwise arrange for one unhook able cat span between hard points on adjacent modules, with tension connections to each end of the trolley wire so the constant-tension when weighted pulls the whole shebang straight.
Study what you have for the construction of pull offs, which enable the side-to-side ‘wiggle’ of the tensioned trolley wire. That may not show at the scale of one module, but should be mimicked in the ‘span’ across several.
When I built my HO NYNH&H layout with NH style catenary in 1997, I had no clue that we would be moving 22 years later. We cut the layout into 8 sections including the Model Memories catenary. It faired far better than I thought it would. I tried to add a photo; doesn’t work.