Heljan O Gauge Class 37 (old generation)

Kit: MS990K; Visaton FRS5; YLR453520; 2x Breeze38x20x10

With some minor modification to the fuel tank, we can slide an MS990K sound decoder in, which means we have all the space we need in the body for some serious speakers! Note that this is an older generation Class 37 model (the latest circa 2024 have XL decoder sockets).

With only very minor grinding with a disc, we can just get the massive Visaton FRS5 50mm hi-fi speaker into this model!

We add wires to the MS990K for everything that we expect to need, and feed the wiring looms up into the main body cavity before attaching the fuel tank again.

With the wiring looms positioned, we can start to build a custom box enclosure for the main speaker.

We'll have to adjust the position later, but we test-fit a 2nd speaker - one of our Traditional YLR453520 boxes, which can be slotted in an at appropriate angle.

Maybe overkill, but for top-end crispness, we add a dual Breeze38x20x10 in each nose too!

Boy, this is going to be loud!!

Please note that these guides are provided as useful resources for you, as-is. YouChoos cannot be held responsible for errors in the information, or for any damage caused to your models or equipment if you choose to follow any of the steps detailed here.