|[railML3]: Defining the <overlap> element [message #2821]
||Sun, 29 August 2021 13:46
Jörg von Lingen
Registered: March 2016
I received the request for clarification on defining the <overlap> element from
Georg Boasson (BaneNOR).
What is the connection between the @length attribute and the subelement
<isLimitedBy> in the <overlap> element? The @length attribute is described as an
alternative way to limit the overlap in meters.
https://wiki3.railml.org/wiki/IL:overlap: Alternatively to a particular limit
the length of the overlap in metres can be given.
Can both these way of defining the overlap coexist and must they both correspond
to each other? The overlap shall be controlled by the Interlocking so it is
typically defined at the position of an Axle counter (or a Track circuit
border). Is it ok to define the overlap as a length independent of train
detectors? And without using the <isLimitedBy> element or can both be defined
independent of each other.
At Bane NOR we calculate the minimum overlap length due to the release speed and
the gradient and therefore we define an overlap length before we have an actual
position. We will typically then place an axle counter close to this position,
but we want to keep and show the calculated length. For us an attribute with a
minimum length of the overlap would be a better definition of the overlap length
than the alternative way.
The answer is yes, both values can coexists with the subelement <isLimitedBy> to
consider the minimum length given in @length. Subsequently I have changed the
description in the wiki:
@length: The physical length of the overlap in metres can be given here as
minimum value in addition or as an alternative to a particular track asset as
<isLimitedBy>: This is the reference to train detection element limiting the
overlap. It can be more than one limiting element. It shall be used in
conjunction to @length and shall respect any value given there as a minimum.
Joerg v. Lingen - Interlocking Coordinator