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Hello, I have a question about MGR Class 56 services. Does anyone know what the maximum speed was for these loaded trains?
I have seen photos with more than 30 HAA wagons and I do not know if it was 45mph or 60mph, I have a doubt what was its maximum speed allowed,
Thanks in advance
Loaded wagons didn't have enough brake force to run at 60 MPH.
Later version of the HAA, the HDA, had the brake force to run at 60 MPH loaded or empty.
From memory I thought it was 60mph loaded and 45mph empty. This is counter intuitive but they are more prone to wheel unloading when empty and although originally 60 mph were reduced to 45 mph when empty as a result of a number of plain line derailments.
Loaded wagons didn't have enough brake force to run at 60 MPH.
Later version of the HAA, the HDA, had the brake force to run at 60 MPH loaded or empty.
Okk thanks, It was the HDAs that could run at 60 mph loaded then. In the pictures I saw (early 90s) I couldn't tell which one they were, but I imagine they could be HAA or HDA.
Okk thanks, It was the HDAs that could run at 60 mph loaded then. In the pictures I saw (early 90s) I couldn't tell which one they were, but I imagine they could be HAA or HDA.
I am stretching my memory here. HAA were originally built without brake discs and the brake calipers operated directly on the wheel pan. in time the wheel centres cracked with the heat input and this is probably why the maximum speed of loaded HAAs was reduced. Later builds (HBA?) had cheek discs and I think HAAs may in time have been modified with cheek disc to increase their speed.
There were various conversions on the HAA/HDA wagons over the years which resulted in changes to the TOPS CARKND such as HCA HFA HMA.
These covered alterations such as the fitting of a canopy to brake modifications.
I am stretching my memory here. HAA were originally built without brake discs and the brake calipers operated directly on the wheel pan. in time the wheel centres cracked with the heat input and this is probably why the maximum speed of loaded HAAs was reduced. Later builds (HBA?) had cheek discs and I think HAAs may in time have been modified with cheek disc to increase their speed.
HDA & CDA china clay wagons were later builds. HBA had manual doors and were used for non MGR coal.
My association with MGRs was from the late 70s with loaded MGRs running class 7 loaded and the return empties class 6.
HAA low brake force only provided enough braking to run at 45 MPH loaded as per table E1 in the Working Manual. Auto brake only operated on one wheel of each axle. diagonally opposites.
There were various conversions on the HAA/HDA wagons over the years which resulted in changes to the TOPS CARKND such as HCA HFA HMA.
These covered alterations such as the fitting of a canopy to brake modifications.
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HDA & CDA china clay wagons were later builds. HBA had manual doors and were used for non MGR coal.
My association with MGRs was from the late 70s with loaded MGRs running class 7 loaded and the return empties class 6.
HAA low brake force only provided enough braking to run at 45 MPH loaded as per table E1 in the Working Manual. Auto brake only operated on one wheel of each axle. diagonally opposites.
Yes, I remember they were only braked on diagonal corners and this resulted in uneven flange wear. Later builds had brake callipers on all wheels. An example of cost cutting not making a saving in the long run.
