This is the system that controls the maximum speed the train operator is allowed to go. This system will change the trains maximum speed based on the track circuit. The speed may also be ‘dialed down’ by LCC or by workers in the field. The maximum speed allowed at any one time is called ‘cab speed’ or ‘ATP speed’. Sometimes the system will automatically reduce the cab speed of a train based on conditions the operator is unaware of, such as being too close to the train ahead. Sometimes cab speed is reduced to zero. Operators will normally call LCC when this happens so whatever caused it can be identified and corrected.
The ATP system will prevent the train from running through an amber signal, getting too close to another train, approaching a misaligned switch or going faster than the allowed ATP speed. IF the operator violates the maximum speed by more than 2 mph, the system will sound an alarm and give the operator 4 seconds to move the operating handle to the Service Brake position until the speed has been reduced to less than the maximum allowable speed, even by 1 mph. If the operator fails to do this, or fails to do it in time, the train will stop. This is called a ‘penalty stop’ and once stopped the operator can continue right away.
Some areas of the track do not have ATP protection and operate in ‘street running’. In this mode of operation, the maximum speed is always set to 35 mph, and there is no automatic reduction for any reason. The system will not prevent the train from doing anything the operator tells it to. The operator could go through a misaligned switch, hit another train, go through an amber signal, etc. But the 35 mph speed limit is imposed the same as if the speed were an ATP speed.
The areas of street running operation are MLK, between Mount Baker station and Norfolk Street in both directions, and the D.S.T.T. from International District Station to Westlake, both directions.
The operator can manually place the train into ‘street mode’ if given permission to do so.
Sometimes when a train has zero cab speed but the controller wants the train to move a little bit anyway you will hear “Clear to go into street and approach the signal” or “Clear to go into street and service the platform”.
Along Martin Luther King, Jr Blvd, the traffic and train signals have a process known as ‘the cascade’ that is supposed to allow the train to go from station to station without having to stop at signals in between.
Sometimes it works, often it doesn’t.
When the operator pulls into Columbia City or Othello southbound, Rainier Beach, Othello or Columbia City northbound, the operator has to initiate a cascade. The operator presses a button when they arrive at the platform that tells the signal system he is there and wants to start a signal cascade. A cascade is started automatically from Mt. Baker southbound.
The operator then has a limited time to load and go to ‘catch the cascade’. Each subsequent signal of the cascade will be the proper signal only for a short time. If the train is delayed, the cascade may be missed.
If the cascade is missed, the operator may have to wait until downstream signals time out of the cascade before trying again. This can cause the train to run late. And since trains can’t go around other trains, if one train runs late, basically every train is running late.
This is why it is SO IMPORTANT for the operator to catch that first signal of the cascade. When it’s time to go, it’s time to GO. If you’re running for the train and the operator closes the doors on you and screams out the station, that’s why.
That is also one reason operators hate it when people hold the doors for slower people. Those people are late for this train, or as operators say, early for the next train.
Please do not hold the doors on the trains. It’s the operators job to close the doors at the most appropriate time and depart. If the operator has some time they will wait for you. If they don’t, holding the door just slows everyone down and makes the entire system even later.
Many operators will close the doors if they see one person break out from a crowd, knowing that person is going to run up and hold the doors for everyone else in their group.
If you think operators don’t remember those people, you are wrong. And when they see you again, they may close the doors on people they wanted to allow on the train just to make sure you can’t delay everyone by holding the doors.
Other things that can goof up a cascade are pedestrians using the buttons to cross the street. They normally have priority over a train that is over a specific distance from the crosswalk.
Fire engines and police vehicles can muck one up too. And sometimes the cascade just fails for no discernible reason
So if you find your train stopping on MLK in between stations, something probably messed the cascade up. Or someone walked in front of the train. That happens a lot too.
This is the system that the operator uses to talk to the signal system. At each end, the operator puts a code into the code panel that tells the system what route the train should take. Should the train go northbound from Angle Lake to University of Washington, or is the train out of service and going to the yard?
This is the system the operator uses to initiate the cascade along MLK and to let other specific systems know the train is ready to go and things need to happen. For example, southbound from SODO station or northbound from Stadium station the operator must let the system know they want to go so the system can start the warning lights and drop the gate arms that stop traffic.
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