Signal block is area of the railway which ends with railtrack dead-end or another signal. If any train entire or it's part is on the block, all signals at enry of the block will become red.

Check out those scenarios for better understanding where exactly are the signal blocks:

Also you should avoid following scenarios - signal block ends with same signal as it start

If you have signal placed in one direction, train will never able to pass it vice-versa direction

To place single-direction semaphore, just after placing semaphore click once again to change direction, and again to change to vice-versa direction, and once again to revert back to double direction type

Chain signal work like normal signal

If no train, it's green

If train in the block, it's red

It works different way in those scenarios:

Chain signal is red also when there is no free exit from the block - chain signal will not allow to pass the train, if the train is not able to exit the block.

If some of the exits from the block are engaged, and some free, chain signal will light up with a blue color. In case train can use the free exit, chain signal allows train to pass, in case train need to access the engaged exit, chain signal not allow train to pass.

Useful when you intend run like 2 trains on single track, you may make short double track where the trains can get around each other



Robust system for your railway network

Legend

Simple - at access to junction place the single direction chain signal, at exit from junction place the normal signal

Follow same rules as T junction just you have 4 directions
Do not place the signals inside the junction

With higher throughput (more trains can pass same time), but bigger place needed.
This time place signals also inside junction.. but you need maintan following rule.. between every crossing or juction need to be at least one signal.. when there will be any two crossing or junction without signals in between.. then it may not works and deadlock with train may occur

Only one train per each direction same time
Train can't turn and return from same direction as he came from

Two trains can enter same direction
Train CAN turn and return from same direction as he came from

Trains which not intend to stop on this station can bypass it

While designing track you should always take into acount an maximum lenght of the train you will run on it, check following fails - trains too long for the track:


Also remember, when you will use robust two track system, there is limit how much train can be present on the track!