| Don Gibson wrote:|
In the 'real world' Double slips exist in passenger 'throat's. In modelling, they function like 2 'Y's back to back, along with taking up less room.
In the real world, the prototype installs them wherever they are appropriate, including singles at locations where a single track main has to allow for a station, and the only space available is the forty meters between a bridge and a tunnel portal. (A station stop requires a switchback maneuver, and uses both curved routes through the double slip as well as the straight route that ISN'T the main line.)
This is an 'exotic' switch that is fine, when it works, but too often gives you disproportionate amounts of trouble. It helps to have a masochistic streak.
Bah, humbug. My hand-laid double slips are less difficult to build than a double crossover and, once built, don't give me any more problems than any other turnout. Having built several, I don't consider them much of a challenge.
There is a reason that most track lines either don't carry, or have dropped them. Power routing is a problem, as are wheel shortings.
The reason that most track lines don't carry double slips is a simple matter of economics - the commercial product is EXPENSIVE! OTOH, the 'makin's' of a hand-built double slip cost less than a single commercial turnout (exclusive of switch machines - the DSS requires two.) Power routing is no more of a problem than power routing for two conventional turnouts laid point to point. Finally, since my open points are electrically disconnected from everything there isn't any way for a back-of-the-flange short to happen.
That said, double slips solve definite problems in the prototype. They don't belong on an average model railroad that isn't faced with similar problems. If, like me, you're modeling a prototype where their use is appropriate, go for it.
Chuck (modeling Central Japan in September, 1964 - with double slip switches)