Drive

As mentioned, Golden Arrow recommend the builder to use two Ibertren Cuckoo chassis but I have many objections against that. It poses some serious problems

	Subject Cuckoo Monarch prototype Frame Inside frame Outside frame Crosshead Two railed croshead One railed crosshead Valve gear None Walschaerts   Moreover the Ibertren Cuckoo is out of production and is by now very rare.
	Once Chivers Finelines seem to have produced a chassis kit to replace the Cuckoo. This seems to be an outside frame, though still no valve gear in sight. Well, I won't delve deep into that matter because these kit seem to have vanished.

So I started looking for a suitable existing model in the N scale range that might be suitable. Surprising I found a diesel locomotive: Roco's BR 290. Its principal dimension in 1:160 come close Monarch's in 1:76

Dimension	Monarch 1:1	BR 290 in 1:160	Monarch in 1:76
Overall wheelbase	5563 mm	59.4 mm	73.2 mm
Bogie wheelbase	991 mm	15.2 mm	13.2 mm
Wheel diameter	609 mm