POINTING THE WAY

Unless you’re building a simple oval of track, your layout is going to need a point or two. Apart from various sizes and geometry, points are available with either ‘dead’ or ‘live’ frogs. The frog is the ‘V’ section of the point, where the routes converge, and the live/dead description refers to its ability to conduct electric power. Given that the twin polarities of the power supply potentially intersect at the frog, we must take steps to prevent short circuits occurring.

‘Dead’ frogs, marketed by Peco as Insulfrogs, consist of a small plastic crossing ‘V’, as well as short insulated fillets within the point blades. These features keep the opposing polarities apart, whatever route is selected. Providing that the track power feeds are located at the ‘toe’ end of each point, Insulfrogs require no extra wiring. However, the short ‘dead’ sections may cause stalling, especially when short wheelbase locomotives are involved.

‘Live’ – or Electrofrog – points lack the plastic insulation breaks, offering the potential for superior running and appearance. Alas, this comes at the cost of extra wiring, with the frog and stock rails at the ‘heel’ end energised at all times, polarity being switched as the route is changed.

This is where short circuits arise, as both stock rails leading from the ‘V’ are energised to the same polarity, contradicting what is being fed to the track beyond the point, meaning that insulated rail joiners must be installed.

The purpose of creating isolated sections of track may vary, according to the demands of the layout. Perhaps you want several locomotives or multiple units to share siding space. Similarly, a terminal station platform benefits from an isolated section at the buffers, permitting another locomotive to back onto the carriages.

Isolation breaks also allow for a layout to be broken into sections that can be operated independently. Interrupting power flow through one or both rails also avoids any potential polarity conflicts, especially where loops and Electrofrog points are concerned. Installing insulation breaks is simple, using plastic rail joiners which help to keep the rails aligned. Alternatively, the rails can be cut and a clear gap created.