diff --git a/co2calculator/parameters.py b/co2calculator/parameters.py
index 518b8ca..77495d1 100644
--- a/co2calculator/parameters.py
+++ b/co2calculator/parameters.py
@@ -8,14 +8,12 @@
     Size,
     CarFuel,
     BusFuel,
-    TrainFuel,
     BusTrainRange,
     FlightRange,
     FlightClass,
     FerryClass,
     ElectricityFuel,
     HeatingFuel,
-    Unit,
     EmissionCategory,
 )
 from typing import Union
@@ -25,17 +23,9 @@ class TrainEmissionParameters(BaseModel):
 
     category: TransportationMode = EmissionCategory.TRANSPORT
     subcategory: TransportationMode = TransportationMode.TRAIN
-    fuel_type: Union[TrainFuel, str] = TrainFuel.AVERAGE
     range: Union[BusTrainRange, str] = BusTrainRange.LONG_DISTANCE
     size: Union[Size, str] = Size.AVERAGE
 
-    @validator("fuel_type", allow_reuse=True)
-    def check_fueltype(cls, v):
-        if isinstance(v, str):
-            assert v.lower() in (item.value for item in TrainFuel)
-            v = v.lower()
-        return TrainFuel(v)
-
     @validator("range", allow_reuse=True)
     def check_range(cls, v):
         if isinstance(v, str):
diff --git a/tests/functional/test_data_code_compliance.py b/tests/functional/test_data_code_compliance.py
index 14b9882..c35fb91 100644
--- a/tests/functional/test_data_code_compliance.py
+++ b/tests/functional/test_data_code_compliance.py
@@ -9,7 +9,6 @@
     emission_factors,
     ElectricityFuel,
     Size,
-    RangeCategory,
     FlightClass,
     FerryClass,
     FlightRange,
diff --git a/tests/unit/test_calculate_mobility.py b/tests/unit/test_calculate_mobility.py
index d3fb08c..48ee316 100644
--- a/tests/unit/test_calculate_mobility.py
+++ b/tests/unit/test_calculate_mobility.py
@@ -107,11 +107,10 @@ def test_calc_co2_bus(
         pytest.param(1162, {}, 38.23, id="defaults on empty"),
         pytest.param(
             1162,
-            {"fuel_type": "electric", "vehicle_range": "long-distance"},
+            {"vehicle_range": "long-distance"},
             37.18,
             id="all optional arguments",
         ),
-        pytest.param(10, {"fuel_type": "diesel"}, 0.7, id="fuel_type: 'electric'"),
     ],
 )
 def test_calc_co2_train(