DP locomotives Part 1 in Tales of the Jointed Track

This also may have been an Open Diary, that I forgot to include in the transfer.

I may have said the term “DP” in some of my entries. DP is an acronym for Distributive Power. Depending on where you live, or if a rail buff, you have seen these. The terms of 2 X 1, 2 X 2, 2 X2 X 2, and I have seen 2 X 4 X 1 on the Joint-Line.

Distributive Power allows the Engineer in the lead consist to control up to four independent DP consists, from one locomotive. This is done via Data Radios, a Computer controlled interface, and electronic magnet valves.

Each DP consist has a receiving unit (DP link) that will take throttle and air brake commands from the Lead link. If there are 2 or more in the DP consist, the are MU’ed via the air brake and MU hoses (Main Reservior-Actuation line-Independent Application Release) and the Jumper Cables inserted between the locomotives. An air test will be made, to insure that they set and release properly and bail off the brake pipe set and are loading up.

When you link up a DP consist and / or a swing helper buried mid train, a couple things must be done. The first thing is the DP’s have to be placed in the train. Yeah I know that seems like a stupid statement, but to make Distributive Power work, the Computers need to do the following:
1) Radio communication between the Data Radios and the Lead Link are established
2) The Computer needs to verify, through the Brake-Pipe, that the DP remotes are “Physically present” in the train. Because that is how the brake valves are synchronized, and not fighting each other for control.

The TRAIN example
The train we are operating is going over a mountain grade territory and subdivision. The train has arrived with 130 cars all grain at 135 to 150 tons per car. It had been originated about 150 miles east of the terminal here. It has been inspected, at another terminal, but will need one here. Why? We are changing the consist(s), and also instituting DP. The train arrived with extra power on the head end. Grade conditions allowed for all the power, five locomotives, to be on the head end. The train is roughly between 19,000 and 19,500 tons. The grade conditions require a helper. The DP will be our helper.

The locomotive that brought this in on the arriving train is not DP equipped. So a “new” operating head end will be made up. This unit will be placed as an MU’ed locomotive, either on the head end or DP and / or swing consist. This work to place the DP’s in and inspect the train has been built into the operating schedule.

The arriving power is taken to the house for inspection and fuel. Sandboxes are filled and cabs cleaned and restocked. Any problems will be corrected or a new locomotive will be found. It has been found out that this train will have a swing helper. The swings will go through to destination. The rearmost DP will be cut off about 250 miles and the power will removed and an ETD placed.

The carmen during this time are working the train. They will check for defects and correct as needed. If it cannot be accomplished, the car is tagged and will be set out as a Bad Order. Brake shoes and brake cylinder piston travel is checked and adjusted. The brake shoes will be changed out as required during this time. The terminal is fortunate, there are no defects, and all that is needed is to place the DP’s and head end on the train.

The hostlers have the rear DP consist and the Swing Helper consist. They will cut off and tie down the swings. A yard crew will double into the swings, release the air, and place them back into the train. The hostler take the rear DP to the rear or the train.

So the entry is not too long, will be continued in Part 2 Thanks.