Western Railroad Discussion > Track Switch Time Lock Question

Since I've only ever worked for shortlines with non-signaled track, I don't have much personal experaince with time-locks. And all of that is just observing class-1 crews dealing with them. In particular the time lock switch at the west end of the yard in Cheney where we frenquently pilot shuttle trains out to the shuttle train elevator at Four Lakes, WA. This one in particular has the habit of refusing to unlock unless the train is within a couple car lengths of it. Based on several years of observing mostly this one time lock, they seem to have three modes. If nothing is between signals on main track, they put a track indication on the main track to drop signals to red and wait about 5~10 minutes to unlock. If there is already a indication on the main track but not close to the switch, they either refuse to unlock or wait a very long time to unlock.. If there is already a indication on the main track close to the switch, they unlock immediately because the train is within sight of the employee operating the switch.

Can someone please clarify the operation of these time locks?

Photo below is of a decommission time lock at a removed switch at Napa St Jct in Spokane, WA in 2006.

Ted Curphey
Ontario, OR

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You have well described the functions of an electric lock.  Its whole function is to prevent a switch from being thrown in front of an approaching train, or being opened without the dispatcher's permission.
 
The whole circuit on the SP at least, and it sounds just like it here, is an FM radiio circuit right at the switch, which tells the lock it is ok to release if an occupancy is stationary within about a car length on each side of the switch.

If the train is in the clear on the side track and the dispr codes the switch, with the main line block clear, the lock should release immediately. 

If the block is occupied, the lock may not release for up to 10 minutes, depending upon the speed of the track.

On the former WP at the East Portola house track, the lock wouldn't release for a movement out of the house track, no matter how long the crew waited.  Somebody figured out that they coud fool the lock into releasing by putting a steel bar across the main track, then opening the box door.  This workd well for years until an FRA signal inspector tried to get it to unlock and it wouldn't.  Then they found out it hadn't ben wired properly on the original installation.
G

What you are describing is called an Electric Switch Lock which is/was described (in my GCOR sixth edition) as:
"Electrically controlled lock that restricts use of of a hand operated switch or derail". Rule 9.18 provides: "To enter
a track within manual interlocking or CTC limits, employees must not open the case door or unlock an electrically
locked switch or derail without track and time or authority from the control operator. 

Your narrative indicates your movement requires you to enter CTC which would require authority from
the control operator, or in this case the DS, prior to unlocking the the case door. Without that authority
the 'system' will treat the opening of the door as a breach and throw the the safety system into 'time',
electrically preventing operating the hand throw switch for the 5-10 minutes you have observed or even
longer depending on the maximum authorized speed in the vicinity. I have seen these 'time outs' as
long as 15 minutes. You state: "If there is already a indication on the main track but not close to the switch,
they either refuse to unlock or wait a very long time to unlock". That's because the 'system' has gone into 
a meltdown when that case door was opened without authority; it doesn't know what's going on out there
in the field so it either refuses to electrically unlock the switch or waits a very long time to ensure any movement
already authorized has come to a stop.

You conclude: "If there is already an indication....they unlock immediately..." You observe correctly, but for a different
reason. In this last scenario the movement on the main track has been authorized, either by issuance
of "track and time" or signal indication; in either case the DS knows the movement has authority and if the train
needs to operate hand throw switches within their authority, the 'system' allows this by 'unlocking' the electric
locked switch when the track circuit senses the wheels are very close or 'on top' of the switch. In this last situation
it may be that the DS manually 'unlocks' the switch(s) needed when the train is observed passing the last controlled signal
in advance of the work area, I'm not exactly sure on this point.

Charlie


 

Charlie, yes this is in CTC. I mostly observe this as the train is already on the mainline trying to enter the yard lead that leads to our shortline. If the train is not close enough to the switch, then it refused to unlock until the train is closer to the switch.

Ted Curphey
Ontario, OR

funnelfan Wrote:
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> Charlie, yes this is in CTC. I mostly observe this
> as the train is already on the mainline trying to
> enter the yard lead that leads to our shortline.
> If the train is not close enough to the switch,
> then it refused to unlock until the train is
> closer to the switch.

This is what I described as the wheels being very close or "on top" of the switch before the electric lock will unlock
to allow the hand throw switch to be thrown. The 'Authority' to occupy the main track was granted by the DS when
he/she issued 'track and time' or lined the train into the block where the electric switch lock is located. 
If a member of the crew were at the lock box (right, like we have lots of crew around these days) that member
could open the lock box when the first wheels of the movement entered the block.
If you were lucky, the 'Locked/Unlocked' window might immediately go to the "Unlocked" position and you were home free; otherwise
the train would have to stop or creep up to the point where the track circuit would recognize a movement and unlock the electric.

Charlie