When managed properly, double ended pools work great! They offer more time at home than single ended pools by using two boards at each terminal, at least on the BNSF. It's a wonder the unions just let them disappear when the UP hub agreements were implemented.

For those who don't know how a double ended pool works, here is how it's done on the BNSF Richmond-Fresno/Calwa pool, which is double ended:

Both Richmond and Fresno are home and away-from-home terminals. Each terminal has two boards: an active board, and an inactive board. When a crew arrives at their away terminal, they are put on the active board, from which crews are called as trains are run. When a crew arrives at their home terminal, they are put on the inactive board, which has a set number of spaces. As more home terminal crews arrive, whoever is on the top of the inactive board moves to the bottom of the active board.
So let's say there are 5 slots on the inactive board (I know, it's an unrealistically small number, just trying to illustrate how it works).

Here is how the Richmond boards would look:

Home Terminal Crews in Bold

Active board:
1. Kyle Broflovski
2. Glenn Quagmire
3. Eric Cartman
4. Ned Flanders
5. Stan Marsh

Inactive Board:
1. Joe Swanson
2. Kenny McCormick
3. Cleveland Brown
4. Batman
5. Harry Potter

A westbound train arrives into Richmond. Peter Griffin is the engineer. His home terminal is Richmond.
Because he is arriving at his home terminal, he is placed at the bottom of the inactive board. The engineer at the top of the inactive board, Joe Swanson, is placed at the bottom of the active board:

Active board:
1. Kyle Broflovski
2. Glenn Quagmire
3. Eric Cartman
4. Ned Flanders
5. Stan Marsh
6. Joe Swanson

Inactive Board:
1. Kenny McCormick
2. Cleveland Brown
3. Batman
4. Harry Potter
5. Peter Griffin

An eastbound is called. Kyle Broflovski, at the top of the active board, is called to take the train. Everyone on the active board moves up, the inactive board stays the same:

Active board:
1. Glenn Quagmire
2. Eric Cartman
3. Ned Flanders
4. Stan Marsh
5. Joe Swanson

Inactive Board:
1. Kenny McCormick
2. Cleveland Brown
3. Batman
4. Harry Potter
5. Peter Griffin

Another westbound arrives. Homer Simpson is the engineer. His home terminal is Fresno.
Because he is arriving at his away terminal, he is placed at the bottom of the active board:

Active board:
1. Glenn Quagmire
2. Eric Cartman
3. Ned Flanders
4. Stan Marsh
5. Joe Swanson
6. Homer Simpson

Inactive Board:
1. Kenny McCormick
2. Cleveland Brown
3. Batman
4. Harry Potter
5. Peter Griffin

So even though Peter Griffin arrived first, Homer Simpson will be the first to leave, and they will each get to spend more time at home as a result.