"Braces & Belt" question.

[george stein]

Writing from USA, so need some UK-based wisdom.  Assume Peco code 100 electrofrog points -- which, of course, have built in spring.  Assume Seep Point Motors # 4 with contacts for powering the frog and "latching."  While, one the one hand, having two systems to assure good contacts seems a bit "braces & belt," on the other hand, removing the Peco spring seems less stress on the Seep solenoids. Silly question I realize, but I suspect there's a fair amount of practical experience behind the choice UK modellers make.  Thanks.

 

George

North Carolina

[BR60103]

George:

It comes down to combinations of whether the point motor has latching and if it is powerful enough to overcome the spring as well.

I've removed a number of springs because the wire from the Tortoise machine bends before it overcomes the spring (I hear that stiffer wire will work).

The old NJ International machines have enough oomph to move anything, including switches that aren't nailed down hard enough.

[grob1234]

George,

 

When wiring peco points in the way you suggest, you're effectively removing the need for the blade to make electrical contact with the stock rail. As you know this is good because it improves the reliability of the point work, ensuring smooth running.

 

If the polarity of the frog is not changing through the relay then essentially you are losing all benefit of using the latching relay in the first place, showing that the wiring has failed in some way. I wouldn't necessarily view it as a "belt and braces" approach, with latching being the primary source and blade contact being the secondary source. I would view latching as being a superior method when wiring points of this type.

 

I wouldn't remove the springs in your points. The seep solenoids will easily overcome the force of the spring. The reason why people do tend to remove the springs is when they are fitting slow action point motors such as Tortoise or Cobalts to their layout, and the Spring would then hinder that slow servo driven operation.

 

So, in my personal opinion, in summary. Wire the points for latching via a relay to ensure frog change polarity, forget about point blade contact, and leave the springs in place. That's what I'd do anyway.

[ejstubbs]

When George refers to "latching" he's referring to the point blade movement - see Gaugemaster's own description of the PM4 - rather than a latching relay.  The frog polarity switching is achieved using a simple SPDT switch built in to the point motor.  As you say, there's no need to use mechanical enhancements to ensure polarity switching by the point blades if you are doing it through a separate switch.  In fact best practice is to break the electrical connection between the point blades and the frog, electrically bind the point blades to their corresponding stock rails, and switch the frog polarity separately.  The Peco code 100 electrofrog points are designed to allow this modification, with small wires between the frog and the switch rails that can be cut, and a dropper wire already attached to the frog for polarity switching.

 

The main purpose of the "latch" on the SEEP PM4 is for hand built turnouts that don't have a spring to keep the point blades in place ie to remove the risk of derailments due to a point blade not properly closing.  Using Peco turnouts there's no need for a separate "latch" so you can use the SEEP PM1 - which has the polarity switch but no "latching" - and not have to worry about whether or not to remove the spring from the Peco point.

 

* Some would say that it is simple to the point of being unreliable.  A latching relay driven by the point motor actuation pulse is arguably a more reliable way to achieve polarity switching when using solenoid point motors.  Electronic equivalents to latching relays can also be used.

[grob1234]

Thank you. I misunderstood the term. sorry for any confusion caused.

[george stein]

Thank you - quite helpful comments.  In the general context of Peco points, I found this recent link interesting.

 

http://www.railwaymodellers.com/m/articles/view/How-to-improve-the-appearance-of-a-Peco-point

 

Again, thank you.

 

George

North Carolina