Digitrax has recently released it's entry into the keep-alive device market.
It is rated at .16F capacitance so it packs plenty of power to assist locos through dirty track and dead frogs.
It comes pre-packaged with a 10-pin Sound harness and Digitrax SP26158B 8 Ohm 1 watt Speaker w/ Enclosure.
It's a pretty good value really considering the unit sells at SBS4DCC for about $25 and the speaker alone would set you back $10.
Unfortunately, as of this writing, Digitrax does not offer the PX112 without the speaker and harness...