Maximum Track Circuit Length

[PJW]

Considerations such as ballast resistance is really for TC calc in mod 5. As ever read the specific question. However you are definitely correct that one of the factors to consider is the quality of the track; continouos welded rail with concrete sleepers and insulations means that ballast resistance is far less of an issue than for traditional jointed track on wood sleepers and thus- from that perspective- a longer track is practicable. However there are also other considerations, such as the ac immunity of dc tracks used within electrified areas which still need to be respected. Having said that, if question asks you to make assumptions re TC lengths without giving too much info that constrains, your statements are perfectly sensible

Hi..
Tryin to share some experience on the DC Track Circuits One.
And the good one in my opinion, what dorothy asked is the main thing that I need to count and calculate into a proposal once received a tender requirement for a TC.

For the DC TC length will be depend on value of ballast resistance, which the resistance it self will be depend on the sleepers type and ballast condition.

Normally in a new project to achieve value of relay drop away and pick up current (configure at varistor), I will put 850m length for the good ballast condition.

By assuming we design with the poor ballast condition (re-signalling) then I would like to present 500m length.

Please be free to correct me if I'm wrong


Yendri