Think most of the modern ones are solar powered, so obviously no good after dark or just before daybreak. Older versions use diesel multiple unit (DMU), but obsolete by now. Insurance might be a problem too, with theft of lead etc being a burden.
Some are lithium battery powered, so heavy to carry and even van mounted can be a drain on the charging system, so best factory fitted and with two split charge relays.
The clogging is universal, I'm afraid, but can be alleviated by squirting WD40 down the tubes every now and then, I'm told.
Let us know how you get on.