Double track tail chaser crossover ideas

[thetalkinlens]

I'm about to embark on a reasonably large scale loft layout tail chaser in 00 scale. The scenic section will use Peco Bullhead track and therefore unifrog points. I intend to power the frogs.  Each individual section of track will have droppers to a bus wire.

 

For various reasons, I feel DC is the best choice over DCC. My 8 year old son has models such as Smokey Joe which I imagine will not be an easy prospect to hard wire a chip, nor do I particularly want to modify his models. My father also has a loft layout running on DC. We frequently share locomotives between each other. I have tried running DCC fitted locomotives with the DC cv option turned on and find the quality of running on DC is usually not as smooth compared to being fitted with a blanking plate. I don't really want to be refitting blanking plates every time models need to run on his layout. I still intend to wire the layout so DCC is a possibility in the future however.

 

So turning to DC, I want to keep things as simple as possible, but at the same time offer flexibility in operation. There will be two running lines - one controller for each. Crossing over between the up and down line is something I would like to explore the options. My fathers layout has one crossover - with isolation on the crossover line. Both controllers then have to be turned on, the correct direction set on each and the power balanced. This is to put it bluntly, arduous and therefore the crossover is hardly ever used.

 

I have included below a first draft of the station track plan. The up and down lines are shown in orange and purple. There is then an mpd in blue and a goods yard in green.

 

Under this plan, the mpd and the goods yard can both be accessed in the same way. From one direction access is direct, then from the opposite line access is made via a diamond crossing. Both would be isolated from the running lines on both rails at the positions where the orange or purple change to blue or green. Which controller is providing power to the goods yard would be by means of a DPDT (double pole double throw) on-on switch. I think that is the correct type of switch, but could be wrong! A second switch of the same nature would provide the same logic for the mpd. A final addition would be some isolation protection for the running line if the diamond is set to be accessed on the opposing line.

 

I've really only followed my own logic with this concept and have no idea what other modellers do. What I would really like to ask is whether this is a sound approach or if there are alternatives?

 

There is for example no direct crossover between the up and down line with this idea.

 

Any feedback and ideas would be greatly welcomed.

[Jeremy Cumberland]

I always think the best thing to start with is to work out what train movements you want, then create a track plan that works with the train movements, work out how it might be signalled (if you are interested in signalling), then work out how to power it. There's quite a lot of overlap between these, and you might, for example, realise when working out signalling that certain movements simply won't work, or that you want additional movements that you hadn't previously thought of.

 

Your track plan is basically sound, with dedicated controllers for the two main lines, and the ability to switch the engine shed and the goods yard to either controller. If you are using common return, you only need single pole double throw (SPDT) switches, but I'd probably choose DPDTs and keep the returns for each zone separate as well. I suggest using switches with a centre off position (on-off-on), so you can isolate the shed and goods yard.

 

If you want a crossover between the up and down lines, you will need additional switchable sections, but these are no more difficult than what you have already. To work out where these sections need to be, you need to think how the crossover is likely to be used.

 

Suppose you had this track plan instead, with no diamond crossongs but a crossover between the two up and down lines instead:

Now, your movements over the crossover are likely to be:

• Passenger train (DMU or auto-train, perhaps) from the right going into the station and then heading back to the right
• Loco from the right heading to the engine shed
• Loco from the engine shed heading to the left
• Goods train from the left heading to the goods yard
• Goods train from the goods yard heading to the left
• Loco from the goods yard going to the engine shed via the station and the crossover
• Loco from the engine shed going to the goods yard via the crossover and the station

All these movements have one thing in common, and that the train always stop immediately before or after the crossover. Where the train stops, you want to make these sections of the main line selectable as well, just like you have made the goods yard and the engine shed selectable. I have drawn these additional switchable areas in black (top main line) and red (bottom main line). These will usually be set to be powered by the top main line controller and the bottom main line controller respectively.

 

Take, for example, the passenger train arriving from the right, coming into the station, then departing to the right. You will driving it into the station with the red track section set for the bottom main line (as usual). Then, while it is stopped, you change the crossover and you also change red track power to the top main line controller, which you then use to drive the train out of the station. As soon as the train is over the crossover, you can reset the crossover and the red power switch.

[thetalkinlens]

Thanks for your reply @Jeremy Cumberland, this certainly gives me something to think about, and to know the general concept of switching the goods yard or mpd control between the up and down controller as a sound approach is good to hear.

[DCB]

I am not at all sure Smoky Joe will run on Bullhead.     I would use centre off DPDT switches, and have one each for Red , Dark Blue, Light Blue and Green.  so any one can be connected to either controller but not both controllers at he same time  The diamond crossing does not sound like a good idea, I would avoid them and use ordinary points as live frog ones are complicated and dead frog promote stalling.

[thetalkinlens]

Thanks @DCB, I have a small shunting layout using Peco bullhead, so will give Smokey Joe a try on it. I'm fairly sure I've done this before and it was ok though.

 

That sounds like a good idea using DPDT switches for all the sections. I will give the track plan a re-work.

[F-UnitMad]

4 hours ago, thetalkinlens said:

 

That sounds like a good idea using DPDT switches for all the sections. I will give the track plan a re-work.

It's what's commonly called "Cab Control". Google should throw up plenty of results. 👍