At Montgomery County's Shady Grove Processing Facility and Transfer Station (MCSGPFaTS) trucks and county residents bring in trash and recyclables, which are loaded into containers like these. The facility's Mi-Jack Travelift stacks the containers and shifts them between carriers.

Per the link below, the station does not accept "railroad tires". I suppose that's a typo.

Link: basic info

When enough trash carriers are filled, they are pushed out in double stacks onto the Met, as seen below. They then wait for escort 18 miles west to Dickerson Generating Station where the trash is incinerated as fuel for electricity generation.

Here is one of those trash trains, pausing on the Met at Derwood, east of Shady Grove.

NEAU is a reporting mark of Seacube Containers. The stack cars bear a NEMX reporting mark of Ogden Martin Systems of Montgomery.

The containers were built by National Steel Car of Hamilton, Ontario.

The Washington Metro Red Line runs adjacent. Between the two lines, B&O's Derwood Station had previously stood on the left.

The trash, but not trashy, escort has arrived from the east. CSX has used symbols D765 and L112 for this trash run.

The pair of engines heads west past the containers...

... where a worker climbs aboard, perhaps after removing a FRED from the west end car...

... and rides to the east end of the containers...

... where the engines pause.

The pause allowed the worker to hang a blue-painted Flashing Rear End Device on the end of the train.

The pair of engines travels back to the west end...

... where it can switch tracks...

... then couple to the containers, and pull them away.

The next track change will be to the spur to the Dickerson Generating Station.

Here's a different trash train as it nears Dickerson.

That's the spur to the generating station on the right. To see more about it, continue with the Dickerson Spur tour.